Release media2 extension

PiperOrigin-RevId: 320351394

RELEASENOTES.md

@@ -231,6 +231,9 @@
         ([#7357](https://github.com/google/ExoPlayer/issues/7357)).
 *   Metadata: Add minimal DVB Application Information Table (AIT) support
     ([#6922](https://github.com/google/ExoPlayer/pull/6922)).
+*   Media2 extension: Publish media2 extension for integrating ExoPlayer with
+    `androidx.media2.common.SessionPlayer` and
+    `androidx.media2.session.MediaSession`.
 *   Cast extension: Implement playlist API and deprecate the old queue
     manipulation API.
 *   Demo app: Retain previous position in list of samples.

core_settings.gradle

@@ -39,6 +39,7 @@ include modulePrefix + 'extension-ima'
 include modulePrefix + 'extension-cast'
 include modulePrefix + 'extension-cronet'
 include modulePrefix + 'extension-mediasession'
+include modulePrefix + 'extension-media2'
 include modulePrefix + 'extension-okhttp'
 include modulePrefix + 'extension-opus'
 include modulePrefix + 'extension-vp9'
@@ -65,6 +66,7 @@ project(modulePrefix + 'extension-ima').projectDir = new File(rootDir, 'extensio
 project(modulePrefix + 'extension-cast').projectDir = new File(rootDir, 'extensions/cast')
 project(modulePrefix + 'extension-cronet').projectDir = new File(rootDir, 'extensions/cronet')
 project(modulePrefix + 'extension-mediasession').projectDir = new File(rootDir, 'extensions/mediasession')
+project(modulePrefix + 'extension-media2').projectDir = new File(rootDir, 'extensions/media2')
 project(modulePrefix + 'extension-okhttp').projectDir = new File(rootDir, 'extensions/okhttp')
 project(modulePrefix + 'extension-opus').projectDir = new File(rootDir, 'extensions/opus')
 project(modulePrefix + 'extension-vp9').projectDir = new File(rootDir, 'extensions/vp9')

extensions/media2/README.md

@@ -0,0 +1,53 @@
+# ExoPlayer Media2 extension #
+
+The Media2 extension provides builders for [SessionPlayer][] and [MediaSession.SessionCallback][] in
+the [Media2 library][].
+
+Compared to [MediaSessionConnector][] that uses [MediaSessionCompat][], this provides finer grained
+control for incoming calls, so you can selectively allow/reject commands per controller.
+
+## Getting the extension ##
+
+The easiest way to use the extension is to add it as a gradle dependency:
+
+```gradle
+implementation 'com.google.android.exoplayer:extension-media2:2.X.X'
+```
+
+where `2.X.X` is the version, which must match the version of the ExoPlayer
+library being used.
+
+Alternatively, you can clone the ExoPlayer repository and depend on the module
+locally. Instructions for doing this can be found in ExoPlayer's
+[top level README][].
+
+[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
+
+## Using the extension ##
+
+### Using `SessionPlayerConnector` ###
+
+`SessionPlayerConnector` is a [SessionPlayer][] implementation wrapping a given `Player`.
+You can use a [SessionPlayer][] instance to build a [MediaSession][], or to set the player
+associated with a [VideoView][] or [MediaControlView][]
+
+### Using `SessionCallbackBuilder` ###
+
+`SessionCallbackBuilder` lets you build a [MediaSession.SessionCallback][] instance given its
+collaborators. You can use a [MediaSession.SessionCallback][] to build a [MediaSession][].
+
+## Links ##
+
+* [Javadoc][]: Classes matching
+  `com.google.android.exoplayer2.ext.media2.*` belong to this module.
+
+[Javadoc]: https://exoplayer.dev/doc/reference/index.html
+
+[SessionPlayer]: https://developer.android.com/reference/androidx/media2/common/SessionPlayer
+[MediaSession]: https://developer.android.com/reference/androidx/media2/session/MediaSession
+[MediaSession.SessionCallback]: https://developer.android.com/reference/androidx/media2/session/MediaSession.SessionCallback
+[Media2 library]: https://developer.android.com/jetpack/androidx/releases/media2
+[MediaSessionCompat]: https://developer.android.com/reference/android/support/v4/media/session/MediaSessionCompat
+[MediaSessionConnector]: https://exoplayer.dev/doc/reference/com/google/android/exoplayer2/ext/mediasession/MediaSessionConnector.html
+[VideoView]: https://developer.android.com/reference/androidx/media2/widget/VideoView
+[MediaControlView]: https://developer.android.com/reference/androidx/media2/widget/MediaControlView

extensions/media2/build.gradle

@@ -0,0 +1,43 @@
+// Copyright 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+apply from: "$gradle.ext.exoplayerSettingsDir/common_library_config.gradle"
+
+android.defaultConfig.minSdkVersion 19
+
+dependencies {
+    implementation project(modulePrefix + 'library-core')
+    implementation 'androidx.collection:collection:' + androidxCollectionVersion
+    implementation 'androidx.concurrent:concurrent-futures:1.0.0'
+    implementation 'com.google.guava:guava:' + guavaVersion
+    api 'androidx.media2:media2-session:1.0.3'
+    compileOnly 'org.checkerframework:checker-compat-qual:' + checkerframeworkCompatVersion
+    compileOnly 'org.checkerframework:checker-qual:' + checkerframeworkVersion
+    compileOnly 'org.jetbrains.kotlin:kotlin-annotations-jvm:' + kotlinAnnotationsVersion
+    androidTestImplementation 'androidx.test.ext:junit:' + androidxTestJUnitVersion
+    androidTestImplementation 'androidx.test:core:' + androidxTestCoreVersion
+    androidTestImplementation 'androidx.test:runner:' + androidxTestRunnerVersion
+    androidTestImplementation 'androidx.test:rules:' + androidxTestRulesVersion
+    androidTestImplementation 'com.google.truth:truth:' + truthVersion
+}
+
+ext {
+    javadocTitle = 'Media2 extension'
+}
+apply from: '../../javadoc_library.gradle'
+
+ext {
+    releaseArtifact = 'extension-media2'
+    releaseDescription = 'Media2 extension for ExoPlayer.'
+}
+apply from: '../../publish.gradle'

extensions/media2/proguard-rules.txt

@@ -0,0 +1,28 @@
+# Proguard rules specific to the media2 extension.
+
+# Constructors and methods accessed via reflection in ExoPlayerUtils.
+-dontnote com.google.android.exoplayer2.source.dash.DashMediaSource$Factory
+-keepclasseswithmembers class com.google.android.exoplayer2.source.dash.DashMediaSource$Factory {
+  public <init>(com.google.android.exoplayer2.upstream.DataSource$Factory);
+  public com.google.android.exoplayer2.source.dash.DashMediaSource$Factory setTag(java.lang.Object);
+}
+-dontnote com.google.android.exoplayer2.source.hls.HlsMediaSource$Factory
+-keepclasseswithmembers class com.google.android.exoplayer2.source.hls.HlsMediaSource$Factory {
+  public <init>(com.google.android.exoplayer2.upstream.DataSource$Factory);
+  public com.google.android.exoplayer2.source.hls.HlsMediaSource$Factory setTag(java.lang.Object);
+}
+-dontnote com.google.android.exoplayer2.source.smoothstreaming.SsMediaSource$Factory
+-keepclasseswithmembers class com.google.android.exoplayer2.source.smoothstreaming.SsMediaSource$Factory {
+  public <init>(com.google.android.exoplayer2.upstream.DataSource$Factory);
+  public com.google.android.exoplayer2.source.smoothstreaming.SsMediaSource$Factory setTag(java.lang.Object);
+}
+
+# Don't warn about checkerframework and Kotlin annotations
+-dontwarn org.checkerframework.**
+-dontwarn kotlin.annotations.jvm.**
+-dontwarn javax.annotation.**
+
+# Work around [internal: b/151134701]: keep non-public versionedparcelable
+# classes.
+-keep class * implements androidx.versionedparcelable.VersionedParcelable
+-keep class androidx.media2.common.MediaParcelUtils$MediaItemParcelImpl

extensions/media2/src/androidTest/AndroidManifest.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2016 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    package="com.google.android.exoplayer2.ext.media2.test">
+
+  <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
+  <uses-permission android:name="android.permission.INTERNET"/>
+  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
+  <uses-sdk/>
+
+  <application
+      android:allowBackup="false"
+      tools:ignore="MissingApplicationIcon,HardcodedDebugMode">
+    <activity android:name="com.google.android.exoplayer2.ext.media2.MediaStubActivity"
+        android:configChanges="keyboardHidden|orientation|screenSize"
+        android:exported="false"
+        android:label="MediaStubActivity"/>
+  </application>
+
+  <instrumentation
+      android:targetPackage="com.google.android.exoplayer2.ext.media2.test"
+      android:name="androidx.test.runner.AndroidJUnitRunner"/>
+
+</manifest>

extensions/media2/src/androidTest/java/com/google/android/exoplayer2/ext/media2/MediaSessionUtilTest.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.os.Looper;
+import android.support.v4.media.session.MediaControllerCompat;
+import android.support.v4.media.session.MediaSessionCompat;
+import androidx.annotation.NonNull;
+import androidx.media2.common.SessionPlayer;
+import androidx.media2.common.SessionPlayer.PlayerResult;
+import androidx.media2.session.MediaSession;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.platform.app.InstrumentationRegistry;
+import com.google.android.exoplayer2.ext.media2.test.R;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Unit test for {@link MediaSessionUtil} */
+@RunWith(AndroidJUnit4.class)
+public class MediaSessionUtilTest {
+  private static final int PLAYER_STATE_CHANGE_WAIT_TIME_MS = 5_000;
+
+  @Rule public final PlayerTestRule playerTestRule = new PlayerTestRule();
+
+  @Test
+  public void getSessionCompatToken_withMediaControllerCompat_returnsValidToken() throws Exception {
+    // Workaround to instantiate MediaSession with public androidx.media dependency.
+    // TODO(b/146536708): Remove this workaround when the relevant change is released via
+    //                    androidx.media 1.2.0.
+    if (Looper.myLooper() == null) {
+      Looper.prepare();
+    }
+
+    Context context = ApplicationProvider.getApplicationContext();
+
+    SessionPlayerConnector sessionPlayerConnector = playerTestRule.getSessionPlayerConnector();
+    MediaSession.SessionCallback sessionCallback =
+        new SessionCallbackBuilder(context, sessionPlayerConnector).build();
+    TestUtils.loadResource(context, R.raw.testmp3_2, sessionPlayerConnector);
+    ListenableFuture<PlayerResult> prepareResult = sessionPlayerConnector.prepare();
+    CountDownLatch latch = new CountDownLatch(1);
+    sessionPlayerConnector.registerPlayerCallback(
+        playerTestRule.getExecutor(),
+        new SessionPlayer.PlayerCallback() {
+          @Override
+          public void onPlayerStateChanged(@NonNull SessionPlayer player, int playerState) {
+            if (playerState == SessionPlayer.PLAYER_STATE_PLAYING) {
+              latch.countDown();
+            }
+          }
+        });
+
+    MediaSession session2 =
+        new MediaSession.Builder(context, sessionPlayerConnector)
+            .setSessionCallback(playerTestRule.getExecutor(), sessionCallback)
+            .build();
+
+    InstrumentationRegistry.getInstrumentation()
+        .runOnMainSync(
+            () -> {
+              try {
+                MediaSessionCompat.Token token =
+                    Assertions.checkNotNull(MediaSessionUtil.getSessionCompatToken(session2));
+                MediaControllerCompat controllerCompat = new MediaControllerCompat(context, token);
+                controllerCompat.getTransportControls().play();
+              } catch (Exception e) {
+                throw new IllegalStateException(e);
+              }
+            });
+    assertThat(
+            prepareResult
+                .get(PLAYER_STATE_CHANGE_WAIT_TIME_MS, TimeUnit.MILLISECONDS)
+                .getResultCode())
+        .isEqualTo(PlayerResult.RESULT_SUCCESS);
+    assertThat(latch.await(PLAYER_STATE_CHANGE_WAIT_TIME_MS, TimeUnit.MILLISECONDS)).isTrue();
+  }
+}

extensions/media2/src/androidTest/java/com/google/android/exoplayer2/ext/media2/MediaStubActivity.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import android.app.Activity;
+import android.app.KeyguardManager;
+import android.content.Context;
+import android.os.Bundle;
+import android.util.Log;
+import android.view.SurfaceHolder;
+import android.view.SurfaceView;
+import android.view.WindowManager;
+import com.google.android.exoplayer2.ext.media2.test.R;
+import com.google.android.exoplayer2.util.Util;
+
+/** Stub activity to play media contents on. */
+public class MediaStubActivity extends Activity {
+  private static final String TAG = "MediaStubActivity";
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    setContentView(R.layout.mediaplayer);
+
+    // disable enter animation.
+    overridePendingTransition(0, 0);
+
+    if (Util.SDK_INT >= 27) {
+      getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+      setTurnScreenOn(true);
+      setShowWhenLocked(true);
+      KeyguardManager keyguardManager =
+          (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);
+      keyguardManager.requestDismissKeyguard(this, null);
+    } else {
+      getWindow()
+          .addFlags(
+              WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
+                  | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
+                  | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
+                  | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
+    }
+  }
+
+  @Override
+  public void finish() {
+    super.finish();
+
+    // disable exit animation.
+    overridePendingTransition(0, 0);
+  }
+
+  @Override
+  protected void onResume() {
+    Log.i(TAG, "onResume");
+    super.onResume();
+  }
+
+  @Override
+  protected void onPause() {
+    Log.i(TAG, "onPause");
+    super.onPause();
+  }
+
+  public SurfaceHolder getSurfaceHolder() {
+    SurfaceView surface = findViewById(R.id.surface);
+    return surface.getHolder();
+  }
+}

extensions/media2/src/androidTest/java/com/google/android/exoplayer2/ext/media2/PlayerTestRule.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import android.content.Context;
+import android.media.AudioManager;
+import android.os.Looper;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.platform.app.InstrumentationRegistry;
+import com.google.android.exoplayer2.SimpleExoPlayer;
+import com.google.android.exoplayer2.source.ConcatenatingMediaSource;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import org.junit.rules.ExternalResource;
+
+/** Rule for tests that use {@link SessionPlayerConnector}. */
+public class PlayerTestRule extends ExternalResource {
+  private Context context;
+  private ExecutorService executor;
+
+  private SessionPlayerConnector sessionPlayerConnector;
+  private SimpleExoPlayer exoPlayer;
+
+  @Override
+  protected void before() {
+    context = ApplicationProvider.getApplicationContext();
+    executor = Executors.newFixedThreadPool(1);
+
+    InstrumentationRegistry.getInstrumentation()
+        .runOnMainSync(
+            () -> {
+              // Initialize AudioManager on the main thread to workaround b/78617702 that
+              // audio focus listener is called on the thread where the AudioManager was
+              // originally initialized.
+              // Without posting this, audio focus listeners wouldn't be called because the
+              // listeners would be posted to the test thread (here) where it waits until the
+              // tests are finished.
+              AudioManager audioManager =
+                  (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+
+              exoPlayer = new SimpleExoPlayer.Builder(context).setLooper(Looper.myLooper()).build();
+              ConcatenatingMediaSource concatenatingMediaSource = new ConcatenatingMediaSource();
+              TimelinePlaylistManager manager =
+                  new TimelinePlaylistManager(context, concatenatingMediaSource);
+              ConcatenatingMediaSourcePlaybackPreparer playbackPreparer =
+                  new ConcatenatingMediaSourcePlaybackPreparer(exoPlayer, concatenatingMediaSource);
+              sessionPlayerConnector =
+                  new SessionPlayerConnector(exoPlayer, manager, playbackPreparer);
+            });
+  }
+
+  @Override
+  protected void after() {
+    if (sessionPlayerConnector != null) {
+      sessionPlayerConnector.close();
+      sessionPlayerConnector = null;
+    }
+    if (exoPlayer != null) {
+      InstrumentationRegistry.getInstrumentation()
+          .runOnMainSync(
+              () -> {
+                exoPlayer.release();
+                exoPlayer = null;
+              });
+    }
+    if (executor != null) {
+      executor.shutdown();
+      executor = null;
+    }
+  }
+
+  public ExecutorService getExecutor() {
+    return executor;
+  }
+
+  public SessionPlayerConnector getSessionPlayerConnector() {
+    return sessionPlayerConnector;
+  }
+
+  public SimpleExoPlayer getSimpleExoPlayer() {
+    return exoPlayer;
+  }
+}

extensions/media2/src/androidTest/java/com/google/android/exoplayer2/ext/media2/SessionCallbackBuilderTest.java

@@ -0,0 +1,710 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import static com.google.android.exoplayer2.ext.media2.TestUtils.assertPlayerResultSuccess;
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth.assertWithMessage;
+
+import android.content.Context;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.Looper;
+import android.text.TextUtils;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+import androidx.media2.common.CallbackMediaItem;
+import androidx.media2.common.DataSourceCallback;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.Rating;
+import androidx.media2.common.SessionPlayer;
+import androidx.media2.common.UriMediaItem;
+import androidx.media2.session.HeartRating;
+import androidx.media2.session.MediaController;
+import androidx.media2.session.MediaSession;
+import androidx.media2.session.SessionCommand;
+import androidx.media2.session.SessionCommandGroup;
+import androidx.media2.session.SessionResult;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.LargeTest;
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.rule.ActivityTestRule;
+import com.google.android.exoplayer2.SimpleExoPlayer;
+import com.google.android.exoplayer2.ext.media2.test.R;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Tests {@link SessionCallbackBuilder}. */
+@RunWith(AndroidJUnit4.class)
+public class SessionCallbackBuilderTest {
+  @Rule
+  public final ActivityTestRule<MediaStubActivity> activityRule =
+      new ActivityTestRule<>(MediaStubActivity.class);
+
+  @Rule public final PlayerTestRule playerTestRule = new PlayerTestRule();
+
+  private static final String MEDIA_SESSION_ID = SessionCallbackBuilderTest.class.getSimpleName();
+  private static final long CONTROLLER_COMMAND_WAIT_TIME_MS = 3_000;
+  private static final long PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS = 10_000;
+  private static final long PLAYER_STATE_CHANGE_WAIT_TIME_MS = 5_000;
+
+  private Context context;
+  private Executor executor;
+  private SessionPlayerConnector sessionPlayerConnector;
+
+  @Before
+  public void setUp() {
+    // Workaround to instantiate MediaSession with public androidx.media dependency.
+    // TODO(jaewan): Remove this workaround when androidx.media 1.2.0 is released.
+    if (Looper.myLooper() == null) {
+      Looper.prepare();
+    }
+    context = ApplicationProvider.getApplicationContext();
+    executor = playerTestRule.getExecutor();
+    sessionPlayerConnector = playerTestRule.getSessionPlayerConnector();
+
+    // Sets the surface to the player for manual check.
+    InstrumentationRegistry.getInstrumentation()
+        .runOnMainSync(
+            () -> {
+              SimpleExoPlayer exoPlayer = playerTestRule.getSimpleExoPlayer();
+              exoPlayer
+                  .getVideoComponent()
+                  .setVideoSurfaceHolder(activityRule.getActivity().getSurfaceHolder());
+            });
+  }
+
+  @Test
+  public void constructor() throws Exception {
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector).build())) {
+      assertPlayerResultSuccess(
+          sessionPlayerConnector.setMediaItem(TestUtils.createMediaItem(context)));
+      assertPlayerResultSuccess(sessionPlayerConnector.prepare());
+
+      OnConnectedListener listener =
+          (controller, allowedCommands) -> {
+            List<Integer> disallowedCommandCodes =
+                Arrays.asList(
+                    SessionCommand.COMMAND_CODE_SESSION_SET_RATING, // no rating callback
+                    SessionCommand.COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM, // no media item provider
+                    SessionCommand
+                        .COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM, // no media item provider
+                    SessionCommand.COMMAND_CODE_PLAYER_SET_MEDIA_ITEM, // no media item provider
+                    SessionCommand.COMMAND_CODE_PLAYER_SET_PLAYLIST, // no media item provider
+                    SessionCommand.COMMAND_CODE_SESSION_REWIND, // no current media item
+                    SessionCommand.COMMAND_CODE_SESSION_FAST_FORWARD // no current media item
+                    );
+            assertDisallowedCommands(disallowedCommandCodes, allowedCommands);
+          };
+      try (MediaController controller = createConnectedController(session, listener, null)) {
+        assertThat(controller.getPlayerState()).isEqualTo(SessionPlayer.PLAYER_STATE_PAUSED);
+      }
+    }
+  }
+
+  @Test
+  public void allowedCommand_withoutPlaylist_disallowsSkipTo() throws Exception {
+    int testRewindIncrementMs = 100;
+    int testFastForwardIncrementMs = 100;
+
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setRatingCallback(
+                    (mediaSession, controller, mediaId, rating) ->
+                        SessionResult.RESULT_ERROR_BAD_VALUE)
+                .setRewindIncrementMs(testRewindIncrementMs)
+                .setFastForwardIncrementMs(testFastForwardIncrementMs)
+                .setMediaItemProvider(new SessionCallbackBuilder.DefaultMediaItemProvider())
+                .build())) {
+      assertPlayerResultSuccess(
+          sessionPlayerConnector.setMediaItem(TestUtils.createMediaItem(context)));
+      assertPlayerResultSuccess(sessionPlayerConnector.prepare());
+
+      CountDownLatch latch = new CountDownLatch(1);
+      OnConnectedListener listener =
+          (controller, allowedCommands) -> {
+            List<Integer> disallowedCommandCodes =
+                Arrays.asList(
+                    SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM,
+                    SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM,
+                    SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM);
+            assertDisallowedCommands(disallowedCommandCodes, allowedCommands);
+            latch.countDown();
+          };
+      try (MediaController controller = createConnectedController(session, listener, null)) {
+        assertThat(latch.await(CONTROLLER_COMMAND_WAIT_TIME_MS, TimeUnit.MILLISECONDS)).isTrue();
+
+        assertSessionResultFailure(controller.skipToNextPlaylistItem());
+        assertSessionResultFailure(controller.skipToPreviousPlaylistItem());
+        assertSessionResultFailure(controller.skipToPlaylistItem(0));
+      }
+    }
+  }
+
+  @Test
+  public void allowedCommand_whenPlaylistSet_allowsSkipTo() throws Exception {
+    List<MediaItem> testPlaylist = new ArrayList<>();
+    testPlaylist.add(TestUtils.createMediaItem(context, R.raw.testvideo));
+    testPlaylist.add(TestUtils.createMediaItem(context, R.raw.sample_not_seekable));
+    int testRewindIncrementMs = 100;
+    int testFastForwardIncrementMs = 100;
+
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setRatingCallback(
+                    (mediaSession, controller, mediaId, rating) ->
+                        SessionResult.RESULT_ERROR_BAD_VALUE)
+                .setRewindIncrementMs(testRewindIncrementMs)
+                .setFastForwardIncrementMs(testFastForwardIncrementMs)
+                .setMediaItemProvider(new SessionCallbackBuilder.DefaultMediaItemProvider())
+                .build())) {
+
+      assertPlayerResultSuccess(sessionPlayerConnector.setPlaylist(testPlaylist, null));
+      assertPlayerResultSuccess(sessionPlayerConnector.prepare());
+
+      OnConnectedListener connectedListener =
+          (controller, allowedCommands) -> {
+            List<Integer> allowedCommandCodes =
+                Arrays.asList(
+                    SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM,
+                    SessionCommand.COMMAND_CODE_PLAYER_SEEK_TO,
+                    SessionCommand.COMMAND_CODE_SESSION_REWIND,
+                    SessionCommand.COMMAND_CODE_SESSION_FAST_FORWARD);
+            assertAllowedCommands(allowedCommandCodes, allowedCommands);
+
+            List<Integer> disallowedCommandCodes =
+                Arrays.asList(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM);
+            assertDisallowedCommands(disallowedCommandCodes, allowedCommands);
+          };
+
+      CountDownLatch allowedCommandChangedLatch = new CountDownLatch(1);
+      OnAllowedCommandsChangedListener allowedCommandChangedListener =
+          (controller, allowedCommands) -> {
+            List<Integer> allowedCommandCodes =
+                Arrays.asList(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM);
+            assertAllowedCommands(allowedCommandCodes, allowedCommands);
+
+            List<Integer> disallowedCommandCodes =
+                Arrays.asList(
+                    SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM,
+                    SessionCommand.COMMAND_CODE_PLAYER_SEEK_TO,
+                    SessionCommand.COMMAND_CODE_SESSION_REWIND,
+                    SessionCommand.COMMAND_CODE_SESSION_FAST_FORWARD);
+            assertDisallowedCommands(disallowedCommandCodes, allowedCommands);
+            allowedCommandChangedLatch.countDown();
+          };
+      try (MediaController controller =
+          createConnectedController(session, connectedListener, allowedCommandChangedListener)) {
+        assertPlayerResultSuccess(sessionPlayerConnector.skipToNextPlaylistItem());
+
+        assertThat(
+                allowedCommandChangedLatch.await(
+                    CONTROLLER_COMMAND_WAIT_TIME_MS, TimeUnit.MILLISECONDS))
+            .isTrue();
+
+        // Also test whether the rewind fails as expected.
+        assertSessionResultFailure(controller.rewind());
+        assertThat(sessionPlayerConnector.getCurrentPosition()).isEqualTo(0);
+        assertThat(controller.getCurrentPosition()).isEqualTo(0);
+      }
+    }
+  }
+
+  @Test
+  public void allowedCommand_afterCurrentMediaItemPrepared_notifiesSeekToAvailable()
+      throws Exception {
+    List<MediaItem> testPlaylist = new ArrayList<>();
+    testPlaylist.add(TestUtils.createMediaItem(context, R.raw.testvideo));
+
+    int resid = R.raw.video_480x360_mp4_h264_1350kbps_30fps_aac_stereo_192kbps_44100hz;
+    TestDataSourceCallback source =
+        TestDataSourceCallback.fromAssetFd(context.getResources().openRawResourceFd(resid));
+    CountDownLatch readAllowedLatch = new CountDownLatch(1);
+    DataSourceCallback dataSource =
+        new DataSourceCallback() {
+          @Override
+          public int readAt(long position, byte[] buffer, int offset, int size) {
+            try {
+              assertThat(
+                      readAllowedLatch.await(
+                          PLAYER_STATE_CHANGE_WAIT_TIME_MS, TimeUnit.MILLISECONDS))
+                  .isTrue();
+            } catch (Exception e) {
+              assertWithMessage("Unexpected exception %s", e).fail();
+            }
+            return source.readAt(position, buffer, offset, size);
+          }
+
+          @Override
+          public long getSize() {
+            return source.getSize();
+          }
+
+          @Override
+          public void close() {
+            source.close();
+          }
+        };
+    testPlaylist.add(new CallbackMediaItem.Builder(dataSource).build());
+
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector).build())) {
+
+      assertPlayerResultSuccess(sessionPlayerConnector.setPlaylist(testPlaylist, null));
+      assertPlayerResultSuccess(sessionPlayerConnector.prepare());
+
+      CountDownLatch seekToAllowedForSecondMediaItem = new CountDownLatch(1);
+      OnAllowedCommandsChangedListener allowedCommandsChangedListener =
+          (controller, allowedCommands) -> {
+            if (allowedCommands.hasCommand(SessionCommand.COMMAND_CODE_PLAYER_SEEK_TO)
+                && controller.getCurrentMediaItemIndex() == 1) {
+              seekToAllowedForSecondMediaItem.countDown();
+            }
+          };
+      try (MediaController controller =
+          createConnectedController(
+              session, /* onConnectedListener= */ null, allowedCommandsChangedListener)) {
+        assertPlayerResultSuccess(sessionPlayerConnector.skipToNextPlaylistItem());
+
+        readAllowedLatch.countDown();
+        assertThat(
+                seekToAllowedForSecondMediaItem.await(
+                    CONTROLLER_COMMAND_WAIT_TIME_MS, TimeUnit.MILLISECONDS))
+            .isTrue();
+      }
+    }
+  }
+
+  @Test
+  public void setRatingCallback_withRatingCallback_receivesRatingCallback() throws Exception {
+    String testMediaId = "testRating";
+    Rating testRating = new HeartRating(true);
+    CountDownLatch latch = new CountDownLatch(1);
+
+    SessionCallbackBuilder.RatingCallback ratingCallback =
+        (session, controller, mediaId, rating) -> {
+          assertThat(mediaId).isEqualTo(testMediaId);
+          assertThat(rating).isEqualTo(testRating);
+          latch.countDown();
+          return SessionResult.RESULT_SUCCESS;
+        };
+
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setRatingCallback(ratingCallback)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {
+        assertSessionResultSuccess(
+            controller.setRating(testMediaId, testRating), CONTROLLER_COMMAND_WAIT_TIME_MS);
+        assertThat(latch.await(0, TimeUnit.MILLISECONDS)).isTrue();
+      }
+    }
+  }
+
+  @Test
+  public void setCustomCommandProvider_withCustomCommandProvider_receivesCustomCommand()
+      throws Exception {
+    SessionCommand testCommand = new SessionCommand("exo.ext.media2.COMMAND", null);
+    CountDownLatch latch = new CountDownLatch(1);
+
+    SessionCallbackBuilder.CustomCommandProvider provider =
+        new SessionCallbackBuilder.CustomCommandProvider() {
+          @Override
+          public SessionResult onCustomCommand(
+              MediaSession session,
+              MediaSession.ControllerInfo controllerInfo,
+              SessionCommand customCommand,
+              @Nullable Bundle args) {
+            assertThat(customCommand.getCustomAction()).isEqualTo(testCommand.getCustomAction());
+            assertThat(args).isNull();
+            latch.countDown();
+            return new SessionResult(SessionResult.RESULT_SUCCESS, null);
+          }
+
+          @Override
+          public SessionCommandGroup getCustomCommands(
+              MediaSession session, MediaSession.ControllerInfo controllerInfo) {
+            return new SessionCommandGroup.Builder().addCommand(testCommand).build();
+          }
+        };
+
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setCustomCommandProvider(provider)
+                .build())) {
+      OnAllowedCommandsChangedListener listener =
+          (controller, allowedCommands) -> {
+            boolean foundCustomCommand = false;
+            for (SessionCommand command : allowedCommands.getCommands()) {
+              if (TextUtils.equals(testCommand.getCustomAction(), command.getCustomAction())) {
+                foundCustomCommand = true;
+                break;
+              }
+            }
+            assertThat(foundCustomCommand).isTrue();
+          };
+      try (MediaController controller = createConnectedController(session, null, listener)) {
+        assertSessionResultSuccess(
+            controller.sendCustomCommand(testCommand, null), CONTROLLER_COMMAND_WAIT_TIME_MS);
+        assertThat(latch.await(0, TimeUnit.MILLISECONDS)).isTrue();
+      }
+    }
+  }
+
+  @LargeTest
+  @Test
+  public void setRewindIncrementMs_withPositiveRewindIncrement_rewinds() throws Exception {
+    int testResId = R.raw.video_480x360_mp4_h264_1350kbps_30fps_aac_stereo_192kbps_44100hz;
+    int testDuration = 10_000;
+    int tolerance = 100;
+    int testSeekPosition = 2_000;
+    int testRewindIncrementMs = 500;
+
+    TestUtils.loadResource(context, testResId, sessionPlayerConnector);
+
+    // seekTo() sometimes takes couple of seconds. Disable default timeout behavior.
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setRewindIncrementMs(testRewindIncrementMs)
+                .setSeekTimeoutMs(0)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {
+        // Prepare first to ensure that seek() works.
+        assertSessionResultSuccess(
+            controller.prepare(), PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS);
+
+        assertThat((float) sessionPlayerConnector.getDuration())
+            .isWithin(tolerance)
+            .of(testDuration);
+        assertSessionResultSuccess(
+            controller.seekTo(testSeekPosition), PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS);
+        assertThat((float) sessionPlayerConnector.getCurrentPosition())
+            .isWithin(tolerance)
+            .of(testSeekPosition);
+
+        // Test rewind
+        assertSessionResultSuccess(
+            controller.rewind(), PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS);
+        assertThat((float) sessionPlayerConnector.getCurrentPosition())
+            .isWithin(tolerance)
+            .of(testSeekPosition - testRewindIncrementMs);
+      }
+    }
+  }
+
+  @LargeTest
+  @Test
+  public void setFastForwardIncrementMs_withPositiveFastForwardIncrement_fastsForward()
+      throws Exception {
+    int testResId = R.raw.video_480x360_mp4_h264_1350kbps_30fps_aac_stereo_192kbps_44100hz;
+    int testDuration = 10_000;
+    int tolerance = 100;
+    int testSeekPosition = 2_000;
+    int testFastForwardIncrementMs = 300;
+
+    TestUtils.loadResource(context, testResId, sessionPlayerConnector);
+
+    // seekTo() sometimes takes couple of seconds. Disable default timeout behavior.
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setFastForwardIncrementMs(testFastForwardIncrementMs)
+                .setSeekTimeoutMs(0)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {
+        // Prepare first to ensure that seek() works.
+        assertSessionResultSuccess(
+            controller.prepare(), PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS);
+
+        assertThat((float) sessionPlayerConnector.getDuration())
+            .isWithin(tolerance)
+            .of(testDuration);
+        assertSessionResultSuccess(
+            controller.seekTo(testSeekPosition), PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS);
+        assertThat((float) sessionPlayerConnector.getCurrentPosition())
+            .isWithin(tolerance)
+            .of(testSeekPosition);
+
+        // Test fast-forward
+        assertSessionResultSuccess(
+            controller.fastForward(), PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS);
+        assertThat((float) sessionPlayerConnector.getCurrentPosition())
+            .isWithin(tolerance)
+            .of(testSeekPosition + testFastForwardIncrementMs);
+      }
+    }
+  }
+
+  @Test
+  public void setMediaItemProvider_withMediaItemProvider_receivesOnCreateMediaItem()
+      throws Exception {
+    int testResId = R.raw.testmp3_2;
+    Uri testMediaIdUri = TestUtils.createResourceUri(context, testResId);
+
+    CountDownLatch providerLatch = new CountDownLatch(1);
+    SessionCallbackBuilder.DefaultMediaItemProvider defaultMediaItemProvider =
+        new SessionCallbackBuilder.DefaultMediaItemProvider();
+    SessionCallbackBuilder.MediaItemProvider provider =
+        (session, controllerInfo, mediaId) -> {
+          assertThat(mediaId).isEqualTo(testMediaIdUri.toString());
+          providerLatch.countDown();
+          return defaultMediaItemProvider.onCreateMediaItem(session, controllerInfo, mediaId);
+        };
+
+    CountDownLatch currentMediaItemChangedLatch = new CountDownLatch(1);
+    sessionPlayerConnector.registerPlayerCallback(
+        executor,
+        new SessionPlayer.PlayerCallback() {
+          @Override
+          public void onCurrentMediaItemChanged(
+              @NonNull SessionPlayer player, @NonNull MediaItem item) {
+            assertThat(((UriMediaItem) item).getUri()).isEqualTo(testMediaIdUri);
+            currentMediaItemChangedLatch.countDown();
+          }
+        });
+
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setMediaItemProvider(provider)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {
+        assertSessionResultSuccess(
+            controller.setMediaItem(testMediaIdUri.toString()),
+            PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS);
+        assertThat(providerLatch.await(0, TimeUnit.MILLISECONDS)).isTrue();
+        assertThat(
+                currentMediaItemChangedLatch.await(
+                    CONTROLLER_COMMAND_WAIT_TIME_MS, TimeUnit.MILLISECONDS))
+            .isTrue();
+      }
+    }
+  }
+
+  @Test
+  public void setSkipCallback_withSkipBackward_receivesOnSkipBackward() throws Exception {
+    CountDownLatch skipBackwardCalledLatch = new CountDownLatch(1);
+    SessionCallbackBuilder.SkipCallback skipCallback =
+        new SessionCallbackBuilder.SkipCallback() {
+          @Override
+          public int onSkipBackward(
+              MediaSession session, MediaSession.ControllerInfo controllerInfo) {
+            skipBackwardCalledLatch.countDown();
+            return SessionResult.RESULT_SUCCESS;
+          }
+
+          @Override
+          public int onSkipForward(
+              MediaSession session, MediaSession.ControllerInfo controllerInfo) {
+            return SessionResult.RESULT_ERROR_NOT_SUPPORTED;
+          }
+        };
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setSkipCallback(skipCallback)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {
+        assertSessionResultSuccess(controller.skipBackward(), CONTROLLER_COMMAND_WAIT_TIME_MS);
+        assertThat(skipBackwardCalledLatch.await(0, TimeUnit.MILLISECONDS)).isTrue();
+      }
+    }
+  }
+
+  @Test
+  public void setSkipCallback_withSkipForward_receivesOnSkipForward() throws Exception {
+    CountDownLatch skipForwardCalledLatch = new CountDownLatch(1);
+    SessionCallbackBuilder.SkipCallback skipCallback =
+        new SessionCallbackBuilder.SkipCallback() {
+          @Override
+          public int onSkipBackward(
+              MediaSession session, MediaSession.ControllerInfo controllerInfo) {
+            return SessionResult.RESULT_ERROR_NOT_SUPPORTED;
+          }
+
+          @Override
+          public int onSkipForward(
+              MediaSession session, MediaSession.ControllerInfo controllerInfo) {
+            skipForwardCalledLatch.countDown();
+            return SessionResult.RESULT_SUCCESS;
+          }
+        };
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setSkipCallback(skipCallback)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {
+        assertSessionResultSuccess(controller.skipForward(), CONTROLLER_COMMAND_WAIT_TIME_MS);
+        assertThat(skipForwardCalledLatch.await(0, TimeUnit.MILLISECONDS)).isTrue();
+      }
+    }
+  }
+
+  @Test
+  public void setPostConnectCallback_afterConnect_receivesOnPostConnect() throws Exception {
+    CountDownLatch postConnectLatch = new CountDownLatch(1);
+    SessionCallbackBuilder.PostConnectCallback postConnectCallback =
+        (session, controllerInfo) -> postConnectLatch.countDown();
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setPostConnectCallback(postConnectCallback)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {
+        assertThat(postConnectLatch.await(CONTROLLER_COMMAND_WAIT_TIME_MS, TimeUnit.MILLISECONDS))
+            .isTrue();
+      }
+    }
+  }
+
+  @Test
+  public void setDisconnectedCallback_afterDisconnect_receivesOnDisconnected() throws Exception {
+    CountDownLatch disconnectedLatch = new CountDownLatch(1);
+    SessionCallbackBuilder.DisconnectedCallback disconnectCallback =
+        (session, controllerInfo) -> disconnectedLatch.countDown();
+    try (MediaSession session =
+        createMediaSession(
+            sessionPlayerConnector,
+            new SessionCallbackBuilder(context, sessionPlayerConnector)
+                .setDisconnectedCallback(disconnectCallback)
+                .build())) {
+      try (MediaController controller = createConnectedController(session)) {}
+      assertThat(disconnectedLatch.await(CONTROLLER_COMMAND_WAIT_TIME_MS, TimeUnit.MILLISECONDS))
+          .isTrue();
+    }
+  }
+
+  private MediaSession createMediaSession(
+      SessionPlayer sessionPlayer, MediaSession.SessionCallback callback) {
+    return new MediaSession.Builder(context, sessionPlayer)
+        .setSessionCallback(executor, callback)
+        .setId(MEDIA_SESSION_ID)
+        .build();
+  }
+
+  private MediaController createConnectedController(MediaSession session) throws Exception {
+    return createConnectedController(session, null, null);
+  }
+
+  private MediaController createConnectedController(
+      MediaSession session,
+      OnConnectedListener onConnectedListener,
+      OnAllowedCommandsChangedListener onAllowedCommandsChangedListener)
+      throws Exception {
+    CountDownLatch latch = new CountDownLatch(1);
+    MediaController.ControllerCallback callback =
+        new MediaController.ControllerCallback() {
+          @Override
+          public void onAllowedCommandsChanged(
+              @NonNull MediaController controller, @NonNull SessionCommandGroup commands) {
+            if (onAllowedCommandsChangedListener != null) {
+              onAllowedCommandsChangedListener.onAllowedCommandsChanged(controller, commands);
+            }
+          }
+
+          @Override
+          public void onConnected(
+              @NonNull MediaController controller, @NonNull SessionCommandGroup allowedCommands) {
+            if (onConnectedListener != null) {
+              onConnectedListener.onConnected(controller, allowedCommands);
+            }
+            latch.countDown();
+          }
+        };
+    MediaController controller =
+        new MediaController.Builder(context)
+            .setSessionToken(session.getToken())
+            .setControllerCallback(ContextCompat.getMainExecutor(context), callback)
+            .build();
+    latch.await();
+    return controller;
+  }
+
+  private static void assertSessionResultSuccess(Future<SessionResult> future) throws Exception {
+    assertSessionResultSuccess(future, CONTROLLER_COMMAND_WAIT_TIME_MS);
+  }
+
+  private static void assertSessionResultSuccess(Future<SessionResult> future, long timeoutMs)
+      throws Exception {
+    SessionResult result = future.get(timeoutMs, TimeUnit.MILLISECONDS);
+    assertThat(result.getResultCode()).isEqualTo(SessionResult.RESULT_SUCCESS);
+  }
+
+  private static void assertSessionResultFailure(Future<SessionResult> future) throws Exception {
+    SessionResult result =
+        future.get(PLAYER_STATE_CHANGE_OVER_SESSION_WAIT_TIME_MS, TimeUnit.MILLISECONDS);
+    assertThat(result.getResultCode()).isNotEqualTo(SessionResult.RESULT_SUCCESS);
+  }
+
+  private static void assertAllowedCommands(
+      List<Integer> expectedAllowedCommandsCode, SessionCommandGroup allowedCommands) {
+    for (int commandCode : expectedAllowedCommandsCode) {
+      assertWithMessage("Command should be allowed, code=" + commandCode)
+          .that(allowedCommands.hasCommand(commandCode))
+          .isTrue();
+    }
+  }
+
+  private static void assertDisallowedCommands(
+      List<Integer> expectedDisallowedCommandsCode, SessionCommandGroup allowedCommands) {
+    for (int commandCode : expectedDisallowedCommandsCode) {
+      assertWithMessage("Command shouldn't be allowed, code=" + commandCode)
+          .that(allowedCommands.hasCommand(commandCode))
+          .isFalse();
+    }
+  }
+
+  private interface OnAllowedCommandsChangedListener {
+    void onAllowedCommandsChanged(MediaController controller, SessionCommandGroup allowedCommands);
+  }
+
+  private interface OnConnectedListener {
+    void onConnected(MediaController controller, SessionCommandGroup allowedCommands);
+  }
+}

extensions/media2/src/androidTest/java/com/google/android/exoplayer2/ext/media2/TestDataSourceCallback.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import android.content.res.AssetFileDescriptor;
+import android.util.Log;
+import androidx.media2.common.DataSourceCallback;
+import java.io.IOException;
+import java.io.InputStream;
+
+/** A DataSourceCallback that reads from a byte array for use in tests. */
+public class TestDataSourceCallback extends DataSourceCallback {
+  private static final String TAG = "TestDataSourceCallback";
+
+  private byte[] data;
+
+  // Read an asset fd into a new byte array media item. Closes afd.
+  public static TestDataSourceCallback fromAssetFd(AssetFileDescriptor afd) throws IOException {
+    try {
+      InputStream in = afd.createInputStream();
+      int size = (int) afd.getDeclaredLength();
+      byte[] data = new byte[size];
+      int writeIndex = 0;
+      int numRead;
+      do {
+        numRead = in.read(data, writeIndex, size - writeIndex);
+        writeIndex += numRead;
+      } while (numRead >= 0);
+      return new TestDataSourceCallback(data);
+    } finally {
+      afd.close();
+    }
+  }
+
+  public TestDataSourceCallback(byte[] data) {
+    this.data = data;
+  }
+
+  @Override
+  public synchronized int readAt(long position, byte[] buffer, int offset, int size) {
+    // Clamp reads past the end of the source.
+    if (position >= data.length) {
+      return -1; // -1 indicates EOF
+    }
+    if (position + size > data.length) {
+      size -= (position + size) - data.length;
+    }
+    System.arraycopy(data, (int) position, buffer, offset, size);
+    return size;
+  }
+
+  @Override
+  public synchronized long getSize() {
+    Log.v(TAG, "getSize: " + data.length);
+    return data.length;
+  }
+
+  // Note: it's fine to keep using this media item after closing it.
+  @Override
+  public synchronized void close() {
+    Log.v(TAG, "close()");
+  }
+}

extensions/media2/src/androidTest/java/com/google/android/exoplayer2/ext/media2/TestUtils.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import static androidx.media2.common.SessionPlayer.PlayerResult.RESULT_SUCCESS;
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.res.Resources;
+import android.net.Uri;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import androidx.media2.common.SessionPlayer;
+import androidx.media2.common.SessionPlayer.PlayerResult;
+import androidx.media2.common.UriMediaItem;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+/** Utilities for tests. */
+public final class TestUtils {
+  private static final long PLAYER_STATE_CHANGE_WAIT_TIME_MS = 5_000;
+
+  public static Uri createResourceUri(Context context, int resId) {
+    Resources resources = context.getResources();
+    return new Uri.Builder()
+        .scheme(ContentResolver.SCHEME_ANDROID_RESOURCE)
+        .authority(resources.getResourcePackageName(resId))
+        .appendPath(resources.getResourceTypeName(resId))
+        .appendPath(resources.getResourceEntryName(resId))
+        .build();
+  }
+
+  public static MediaItem createMediaItem(Context context) {
+    return createMediaItem(context, com.google.android.exoplayer2.ext.media2.test.R.raw.testvideo);
+  }
+
+  public static MediaItem createMediaItem(Context context, int resId) {
+    Uri testVideoUri = createResourceUri(context, resId);
+    String resourceName = context.getResources().getResourceName(resId);
+    MediaMetadata metadata =
+        new MediaMetadata.Builder()
+            .putString(MediaMetadata.METADATA_KEY_MEDIA_ID, resourceName)
+            .build();
+    return new UriMediaItem.Builder(testVideoUri).setMetadata(metadata).build();
+  }
+
+  public static List<MediaItem> createPlaylist(Context context, int size) {
+    List<MediaItem> items = new ArrayList<>();
+    for (int i = 0; i < size; ++i) {
+      items.add(createMediaItem(context));
+    }
+    return items;
+  }
+
+  public static void loadResource(Context context, int resId, SessionPlayer sessionPlayer)
+      throws Exception {
+    Uri testUri = TestUtils.createResourceUri(context, resId);
+    MediaItem mediaItem = createMediaItem(context, resId);
+    assertPlayerResultSuccess(sessionPlayer.setMediaItem(mediaItem));
+  }
+
+  public static void assertPlayerResultSuccess(Future<PlayerResult> future) throws Exception {
+    assertPlayerResult(future, RESULT_SUCCESS);
+  }
+
+  public static void assertPlayerResult(
+      Future<PlayerResult> future, /* @PlayerResult.ResultCode */ int playerResult)
+      throws Exception {
+    assertThat(future).isNotNull();
+    PlayerResult result = future.get(PLAYER_STATE_CHANGE_WAIT_TIME_MS, TimeUnit.MILLISECONDS);
+    assertThat(result).isNotNull();
+    assertThat(result.getResultCode()).isEqualTo(playerResult);
+  }
+
+  private TestUtils() {
+    // Prevent from instantiation.
+  }
+}

extensions/media2/src/androidTest/res/layout/mediaplayer.xml

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2019 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical"
+    android:keepScreenOn="true"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <SurfaceView android:id="@+id/surface"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_weight="1">
+    </SurfaceView>
+
+    <SurfaceView android:id="@+id/surface2"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_weight="1">
+    </SurfaceView>
+
+    <SurfaceView android:id="@+id/surface3"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_weight="1">
+    </SurfaceView>
+
+</LinearLayout>

extensions/media2/src/main/AndroidManifest.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2019 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<manifest package="com.google.android.exoplayer2.ext.media2"/>

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/ConcatenatingMediaSourcePlaybackPreparer.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import com.google.android.exoplayer2.ExoPlayer;
+import com.google.android.exoplayer2.PlaybackPreparer;
+import com.google.android.exoplayer2.source.ConcatenatingMediaSource;
+import com.google.android.exoplayer2.util.Assertions;
+
+/** Prepares an {@link ExoPlayer} instance with a {@link ConcatenatingMediaSource}. */
+public final class ConcatenatingMediaSourcePlaybackPreparer implements PlaybackPreparer {
+
+  private final ExoPlayer exoPlayer;
+  private final ConcatenatingMediaSource concatenatingMediaSource;
+
+  /**
+   * Creates a concatenating media source playback preparer.
+   *
+   * @param exoPlayer The player to prepare.
+   * @param concatenatingMediaSource The concatenating media source with which to prepare the
+   *     player.
+   */
+  public ConcatenatingMediaSourcePlaybackPreparer(
+      ExoPlayer exoPlayer, ConcatenatingMediaSource concatenatingMediaSource) {
+    this.exoPlayer = exoPlayer;
+    this.concatenatingMediaSource = Assertions.checkNotNull(concatenatingMediaSource);
+  }
+
+  @Override
+  public void preparePlayback() {
+    exoPlayer.prepare(concatenatingMediaSource);
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/DataSourceCallbackDataSource.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import android.net.Uri;
+import androidx.annotation.Nullable;
+import androidx.media2.common.DataSourceCallback;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.upstream.BaseDataSource;
+import com.google.android.exoplayer2.upstream.DataSource;
+import com.google.android.exoplayer2.upstream.DataSpec;
+import com.google.android.exoplayer2.util.Assertions;
+import java.io.EOFException;
+import java.io.IOException;
+
+/** An ExoPlayer {@link DataSource} for reading from a {@link DataSourceCallback}. */
+/* package */ final class DataSourceCallbackDataSource extends BaseDataSource {
+
+  /**
+   * Returns a factory for {@link DataSourceCallbackDataSource}s.
+   *
+   * @return A factory for data sources that read from the data source callback.
+   */
+  public static DataSource.Factory getFactory(DataSourceCallback dataSourceCallback) {
+    Assertions.checkNotNull(dataSourceCallback);
+    return () -> new DataSourceCallbackDataSource(dataSourceCallback);
+  }
+
+  private final DataSourceCallback dataSourceCallback;
+
+  @Nullable private Uri uri;
+  private long position;
+  private long bytesRemaining;
+  private boolean opened;
+
+  public DataSourceCallbackDataSource(DataSourceCallback dataSourceCallback) {
+    super(/* isNetwork= */ false);
+    this.dataSourceCallback = Assertions.checkNotNull(dataSourceCallback);
+  }
+
+  @Override
+  public long open(DataSpec dataSpec) throws IOException {
+    uri = dataSpec.uri;
+    position = dataSpec.position;
+    transferInitializing(dataSpec);
+    long dataSourceCallbackSize = dataSourceCallback.getSize();
+    if (dataSpec.length != C.LENGTH_UNSET) {
+      bytesRemaining = dataSpec.length;
+    } else if (dataSourceCallbackSize != -1) {
+      bytesRemaining = dataSourceCallbackSize - position;
+    } else {
+      bytesRemaining = C.LENGTH_UNSET;
+    }
+    opened = true;
+    transferStarted(dataSpec);
+    return bytesRemaining;
+  }
+
+  @Override
+  public int read(byte[] buffer, int offset, int readLength) throws IOException {
+    if (readLength == 0) {
+      return 0;
+    } else if (bytesRemaining == 0) {
+      return C.RESULT_END_OF_INPUT;
+    }
+    int bytesToRead =
+        bytesRemaining == C.LENGTH_UNSET ? readLength : (int) Math.min(bytesRemaining, readLength);
+    int bytesRead = dataSourceCallback.readAt(position, buffer, offset, bytesToRead);
+    if (bytesRead == -1) {
+      if (bytesRemaining != C.LENGTH_UNSET) {
+        throw new EOFException();
+      }
+      return C.RESULT_END_OF_INPUT;
+    }
+    position += bytesRead;
+    if (bytesRemaining != C.LENGTH_UNSET) {
+      bytesRemaining -= bytesRead;
+    }
+    bytesTransferred(bytesRead);
+    return bytesRead;
+  }
+
+  @Override
+  @Nullable
+  public Uri getUri() {
+    return uri;
+  }
+
+  @Override
+  public void close() {
+    uri = null;
+    if (opened) {
+      opened = false;
+      transferEnded();
+    }
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/MediaSessionUtil.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import android.annotation.SuppressLint;
+import android.support.v4.media.session.MediaSessionCompat;
+import androidx.media2.session.MediaSession;
+
+/** Utility methods to use {@link MediaSession} with other existing Exo modules. */
+public final class MediaSessionUtil {
+
+  /** Gets the {@link MediaSessionCompat.Token} from the {@link MediaSession}. */
+  // TODO(b/152764014): Deprecate this API when MediaSession#getSessionCompatToken() is released.
+  public static MediaSessionCompat.Token getSessionCompatToken(MediaSession session2) {
+    @SuppressLint("RestrictedApi")
+    @SuppressWarnings("RestrictTo")
+    MediaSessionCompat sessionCompat = session2.getSessionCompat();
+    return sessionCompat.getSessionToken();
+  }
+
+  private MediaSessionUtil() {
+    // Prevent from instantiation.
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/PlayerCommandQueue.java

@@ -0,0 +1,452 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import androidx.annotation.GuardedBy;
+import androidx.annotation.IntDef;
+import androidx.annotation.Nullable;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import androidx.media2.common.SessionPlayer;
+import androidx.media2.common.SessionPlayer.PlayerResult;
+import com.google.android.exoplayer2.util.Log;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.TimeUnit;
+
+/** Manages the queue of player actions and handles running them one by one. */
+/* package */ class PlayerCommandQueue implements AutoCloseable {
+
+  private static final String TAG = "PlayerCommandQueue";
+  private static final boolean DEBUG = false;
+
+  // Redefine command codes rather than using constants from SessionCommand here, because command
+  // code for setAudioAttribute() is missing in SessionCommand.
+  /** Command code for {@link SessionPlayer#setAudioAttributes}. */
+  public static final int COMMAND_CODE_PLAYER_SET_AUDIO_ATTRIBUTES = 0;
+
+  /** Command code for {@link SessionPlayer#play} */
+  public static final int COMMAND_CODE_PLAYER_PLAY = 1;
+
+  /** Command code for {@link SessionPlayer#replacePlaylistItem(int, MediaItem)} */
+  public static final int COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM = 2;
+
+  /** Command code for {@link SessionPlayer#skipToPreviousPlaylistItem()} */
+  public static final int COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM = 3;
+
+  /** Command code for {@link SessionPlayer#skipToNextPlaylistItem()} */
+  public static final int COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM = 4;
+
+  /** Command code for {@link SessionPlayer#skipToPlaylistItem(int)} */
+  public static final int COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM = 5;
+
+  /** Command code for {@link SessionPlayer#updatePlaylistMetadata(MediaMetadata)} */
+  public static final int COMMAND_CODE_PLAYER_UPDATE_LIST_METADATA = 6;
+
+  /** Command code for {@link SessionPlayer#setRepeatMode(int)} */
+  public static final int COMMAND_CODE_PLAYER_SET_REPEAT_MODE = 7;
+
+  /** Command code for {@link SessionPlayer#setShuffleMode(int)} */
+  public static final int COMMAND_CODE_PLAYER_SET_SHUFFLE_MODE = 8;
+
+  /** Command code for {@link SessionPlayer#setMediaItem(MediaItem)} */
+  public static final int COMMAND_CODE_PLAYER_SET_MEDIA_ITEM = 9;
+
+  /** Command code for {@link SessionPlayer#seekTo(long)} */
+  public static final int COMMAND_CODE_PLAYER_SEEK_TO = 10;
+
+  /** Command code for {@link SessionPlayer#prepare()} */
+  public static final int COMMAND_CODE_PLAYER_PREPARE = 11;
+
+  /** Command code for {@link SessionPlayer#setPlaybackSpeed(float)} */
+  public static final int COMMAND_CODE_PLAYER_SET_SPEED = 12;
+
+  /** Command code for {@link SessionPlayer#pause()} */
+  public static final int COMMAND_CODE_PLAYER_PAUSE = 13;
+
+  /** Command code for {@link SessionPlayer#setPlaylist(List, MediaMetadata)} */
+  public static final int COMMAND_CODE_PLAYER_SET_PLAYLIST = 14;
+
+  /** Command code for {@link SessionPlayer#addPlaylistItem(int, MediaItem)} */
+  public static final int COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM = 15;
+
+  /** Command code for {@link SessionPlayer#removePlaylistItem(int)} */
+  public static final int COMMAND_CODE_PLAYER_REMOVE_PLAYLIST_ITEM = 16;
+
+  /** List of session commands whose result would be set after the command is finished. */
+  @Documented
+  @Retention(RetentionPolicy.SOURCE)
+  @IntDef(
+      value = {
+        COMMAND_CODE_PLAYER_SET_AUDIO_ATTRIBUTES,
+        COMMAND_CODE_PLAYER_PLAY,
+        COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM,
+        COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM,
+        COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM,
+        COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM,
+        COMMAND_CODE_PLAYER_UPDATE_LIST_METADATA,
+        COMMAND_CODE_PLAYER_SET_REPEAT_MODE,
+        COMMAND_CODE_PLAYER_SET_SHUFFLE_MODE,
+        COMMAND_CODE_PLAYER_SET_MEDIA_ITEM,
+        COMMAND_CODE_PLAYER_SEEK_TO,
+        COMMAND_CODE_PLAYER_PREPARE,
+        COMMAND_CODE_PLAYER_SET_SPEED,
+        COMMAND_CODE_PLAYER_PAUSE,
+        COMMAND_CODE_PLAYER_SET_PLAYLIST,
+        COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM,
+        COMMAND_CODE_PLAYER_REMOVE_PLAYLIST_ITEM,
+      })
+  public @interface CommandCode {}
+
+  /** Command whose result would be set later via listener after the command is finished. */
+  @Documented
+  @Retention(RetentionPolicy.SOURCE)
+  @IntDef(
+      value = {COMMAND_CODE_PLAYER_PREPARE, COMMAND_CODE_PLAYER_PLAY, COMMAND_CODE_PLAYER_PAUSE})
+  public @interface AsyncCommandCode {}
+
+  // Should be only used on the handler.
+  private final PlayerWrapper player;
+  private final PlayerHandler handler;
+  private final Object lock;
+
+  @GuardedBy("lock")
+  private final Deque<PlayerCommand> pendingPlayerCommandQueue;
+
+  @GuardedBy("lock")
+  private boolean closed;
+
+  // Should be only used on the handler.
+  @Nullable private AsyncPlayerCommandResult pendingAsyncPlayerCommandResult;
+
+  public PlayerCommandQueue(PlayerWrapper player, PlayerHandler handler) {
+    this.player = player;
+    this.handler = handler;
+    lock = new Object();
+    pendingPlayerCommandQueue = new ArrayDeque<>();
+  }
+
+  @Override
+  public void close() {
+    synchronized (lock) {
+      if (closed) {
+        return;
+      }
+      closed = true;
+    }
+    reset();
+  }
+
+  public void reset() {
+    handler.removeCallbacksAndMessages(/* token= */ null);
+    List<PlayerCommand> queue;
+    synchronized (lock) {
+      queue = new ArrayList<>(pendingPlayerCommandQueue);
+      pendingPlayerCommandQueue.clear();
+    }
+    for (PlayerCommand playerCommand : queue) {
+      playerCommand.result.set(
+          new PlayerResult(PlayerResult.RESULT_INFO_SKIPPED, /* item= */ null));
+    }
+  }
+
+  public ListenableFuture<PlayerResult> addCommand(
+      @CommandCode int commandCode, Callable<Boolean> command) {
+    return addCommand(commandCode, command, /* tag= */ null);
+  }
+
+  public ListenableFuture<PlayerResult> addCommand(
+      @CommandCode int commandCode, Callable<Boolean> command, @Nullable Object tag) {
+    SettableFuture<PlayerResult> result = SettableFuture.create();
+    synchronized (lock) {
+      if (closed) {
+        // OK to set result with lock hold because developers cannot add listener here.
+        result.set(new PlayerResult(PlayerResult.RESULT_ERROR_INVALID_STATE, /* item= */ null));
+        return result;
+      }
+      PlayerCommand playerCommand = new PlayerCommand(commandCode, command, result, tag);
+      result.addListener(
+          () -> {
+            if (result.isCancelled()) {
+              boolean isCommandPending;
+              synchronized (lock) {
+                isCommandPending = pendingPlayerCommandQueue.remove(playerCommand);
+              }
+              if (isCommandPending) {
+                result.set(
+                    new PlayerResult(
+                        PlayerResult.RESULT_INFO_SKIPPED, player.getCurrentMediaItem()));
+                if (DEBUG) {
+                  Log.d(TAG, "canceled " + playerCommand);
+                }
+              }
+              if (pendingAsyncPlayerCommandResult != null
+                  && pendingAsyncPlayerCommandResult.result == result) {
+                pendingAsyncPlayerCommandResult = null;
+              }
+            }
+            processPendingCommandOnHandler();
+          },
+          handler::postOrRun);
+      if (DEBUG) {
+        Log.d(TAG, "adding " + playerCommand);
+      }
+      pendingPlayerCommandQueue.add(playerCommand);
+    }
+    processPendingCommand();
+    return result;
+  }
+
+  public void notifyCommandError() {
+    handler.postOrRun(
+        () -> {
+          @Nullable AsyncPlayerCommandResult pendingResult = pendingAsyncPlayerCommandResult;
+          if (pendingResult == null) {
+            if (DEBUG) {
+              Log.d(TAG, "Ignoring notifyCommandError(). No pending async command.");
+            }
+            return;
+          }
+          pendingResult.result.set(
+              new PlayerResult(PlayerResult.RESULT_ERROR_UNKNOWN, player.getCurrentMediaItem()));
+          pendingAsyncPlayerCommandResult = null;
+          if (DEBUG) {
+            Log.d(TAG, "error on " + pendingResult);
+          }
+          processPendingCommandOnHandler();
+        });
+  }
+
+  public void notifyCommandCompleted(@AsyncCommandCode int completedCommandCode) {
+    if (DEBUG) {
+      Log.d(TAG, "notifyCommandCompleted, completedCommandCode=" + completedCommandCode);
+    }
+    handler.postOrRun(
+        () -> {
+          @Nullable AsyncPlayerCommandResult pendingResult = pendingAsyncPlayerCommandResult;
+          if (pendingResult == null || pendingResult.commandCode != completedCommandCode) {
+            if (DEBUG) {
+              Log.d(
+                  TAG,
+                  "Unexpected Listener is notified from the Player. Player may be used"
+                      + " directly rather than "
+                      + toLogFriendlyString(completedCommandCode));
+            }
+            return;
+          }
+          pendingResult.result.set(
+              new PlayerResult(PlayerResult.RESULT_SUCCESS, player.getCurrentMediaItem()));
+          pendingAsyncPlayerCommandResult = null;
+          if (DEBUG) {
+            Log.d(TAG, "completed " + pendingResult);
+          }
+          processPendingCommandOnHandler();
+        });
+  }
+
+  private void processPendingCommand() {
+    handler.postOrRun(this::processPendingCommandOnHandler);
+  }
+
+  private void processPendingCommandOnHandler() {
+    while (pendingAsyncPlayerCommandResult == null) {
+      @Nullable PlayerCommand playerCommand;
+      synchronized (lock) {
+        playerCommand = pendingPlayerCommandQueue.poll();
+      }
+      if (playerCommand == null) {
+        return;
+      }
+
+      int commandCode = playerCommand.commandCode;
+      // Check if it's @AsyncCommandCode
+      boolean asyncCommand = isAsyncCommand(playerCommand.commandCode);
+
+      // Continuous COMMAND_CODE_PLAYER_SEEK_TO can be skipped.
+      if (commandCode == COMMAND_CODE_PLAYER_SEEK_TO) {
+        @Nullable List<PlayerCommand> skippingCommands = null;
+        while (true) {
+          synchronized (lock) {
+            @Nullable PlayerCommand pendingCommand = pendingPlayerCommandQueue.peek();
+            if (pendingCommand == null || pendingCommand.commandCode != commandCode) {
+              break;
+            }
+            pendingPlayerCommandQueue.poll();
+            if (skippingCommands == null) {
+              skippingCommands = new ArrayList<>();
+            }
+            skippingCommands.add(playerCommand);
+            playerCommand = pendingCommand;
+          }
+        }
+        if (skippingCommands != null) {
+          for (PlayerCommand skippingCommand : skippingCommands) {
+            skippingCommand.result.set(
+                new PlayerResult(PlayerResult.RESULT_INFO_SKIPPED, player.getCurrentMediaItem()));
+            if (DEBUG) {
+              Log.d(TAG, "skipping pending command, " + skippingCommand);
+            }
+          }
+        }
+      }
+
+      if (asyncCommand) {
+        // Result would come later, via #notifyCommandCompleted().
+        // Set pending player result first because it may be notified while the command is running.
+        pendingAsyncPlayerCommandResult =
+            new AsyncPlayerCommandResult(commandCode, playerCommand.result);
+      }
+
+      if (DEBUG) {
+        Log.d(TAG, "start processing command, " + playerCommand);
+      }
+
+      int resultCode;
+      if (player.hasError()) {
+        resultCode = PlayerResult.RESULT_ERROR_INVALID_STATE;
+      } else {
+        try {
+          boolean handled = playerCommand.command.call();
+          resultCode = handled ? PlayerResult.RESULT_SUCCESS : PlayerResult.RESULT_INFO_SKIPPED;
+        } catch (IllegalStateException e) {
+          resultCode = PlayerResult.RESULT_ERROR_INVALID_STATE;
+        } catch (IllegalArgumentException | IndexOutOfBoundsException e) {
+          resultCode = PlayerResult.RESULT_ERROR_BAD_VALUE;
+        } catch (SecurityException e) {
+          resultCode = PlayerResult.RESULT_ERROR_PERMISSION_DENIED;
+        } catch (Exception e) {
+          resultCode = PlayerResult.RESULT_ERROR_UNKNOWN;
+        }
+      }
+      if (DEBUG) {
+        Log.d(TAG, "command processed, " + playerCommand);
+      }
+
+      if (asyncCommand) {
+        if (resultCode != PlayerResult.RESULT_SUCCESS
+            && pendingAsyncPlayerCommandResult != null
+            && playerCommand.result == pendingAsyncPlayerCommandResult.result) {
+          pendingAsyncPlayerCommandResult = null;
+          playerCommand.result.set(new PlayerResult(resultCode, player.getCurrentMediaItem()));
+        }
+      } else {
+        playerCommand.result.set(new PlayerResult(resultCode, player.getCurrentMediaItem()));
+      }
+    }
+  }
+
+  private static String toLogFriendlyString(@AsyncCommandCode int commandCode) {
+    switch (commandCode) {
+      case COMMAND_CODE_PLAYER_PLAY:
+        return "SessionPlayerConnector#play()";
+      case COMMAND_CODE_PLAYER_PAUSE:
+        return "SessionPlayerConnector#pause()";
+      case COMMAND_CODE_PLAYER_PREPARE:
+        return "SessionPlayerConnector#prepare()";
+      default:
+        // Never happens.
+        throw new IllegalStateException();
+    }
+  }
+
+  private static boolean isAsyncCommand(@CommandCode int commandCode) {
+    switch (commandCode) {
+      case COMMAND_CODE_PLAYER_PLAY:
+      case COMMAND_CODE_PLAYER_PAUSE:
+      case COMMAND_CODE_PLAYER_PREPARE:
+        return true;
+    }
+    return false;
+  }
+
+  private static final class AsyncPlayerCommandResult {
+    @AsyncCommandCode public final int commandCode;
+    public final SettableFuture<PlayerResult> result;
+
+    public AsyncPlayerCommandResult(
+        @AsyncCommandCode int commandCode, SettableFuture<PlayerResult> result) {
+      this.commandCode = commandCode;
+      this.result = result;
+    }
+
+    @Override
+    public String toString() {
+      StringBuilder stringBuilder =
+          new StringBuilder("AsyncPlayerCommandResult {commandCode=")
+              .append(commandCode)
+              .append(", result=")
+              .append(result.hashCode());
+      if (result.isDone()) {
+        try {
+          int resultCode = result.get(/* timeout= */ 0, TimeUnit.MILLISECONDS).getResultCode();
+          stringBuilder.append(", resultCode=").append(resultCode);
+        } catch (Exception e) {
+          // pass-through.
+        }
+      }
+      stringBuilder.append("}");
+      return stringBuilder.toString();
+    }
+  }
+
+  private static final class PlayerCommand {
+    public final int commandCode;
+    public final Callable<Boolean> command;
+    // Result shouldn't be set with lock held, because it may trigger listener set by developers.
+    public final SettableFuture<PlayerResult> result;
+    @Nullable private final Object tag;
+
+    public PlayerCommand(
+        int commandCode,
+        Callable<Boolean> command,
+        SettableFuture<PlayerResult> result,
+        @Nullable Object tag) {
+      this.commandCode = commandCode;
+      this.command = command;
+      this.result = result;
+      this.tag = tag;
+    }
+
+    @Override
+    public String toString() {
+      StringBuilder stringBuilder =
+          new StringBuilder("PlayerCommand {commandCode=")
+              .append(commandCode)
+              .append(", result=")
+              .append(result.hashCode());
+      if (result.isDone()) {
+        try {
+          int resultCode = result.get(/* timeout= */ 0, TimeUnit.MILLISECONDS).getResultCode();
+          stringBuilder.append(", resultCode=").append(resultCode);
+        } catch (Exception e) {
+          // pass-through.
+        }
+      }
+      if (tag != null) {
+        stringBuilder.append(", tag=").append(tag);
+      }
+      stringBuilder.append("}");
+      return stringBuilder.toString();
+    }
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/PlayerHandler.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import android.os.Handler;
+import android.os.Looper;
+
+/** A {@link Handler} that provides {@link #postOrRun(Runnable)}. */
+/* package */ final class PlayerHandler extends Handler {
+  public PlayerHandler(Looper looper) {
+    super(looper);
+  }
+
+  /**
+   * Posts the {@link Runnable} if the calling thread differs with the {@link Looper} of this
+   * handler. Otherwise, runs the runnable directly.
+   *
+   * @param r A runnable to either post or run.
+   * @return {@code true} if it's successfully run. {@code false} otherwise.
+   */
+  public boolean postOrRun(Runnable r) {
+    if (Thread.currentThread() != getLooper().getThread()) {
+      return post(r);
+    }
+    r.run();
+    return true;
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/PlayerWrapper.java

@@ -0,0 +1,533 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import androidx.annotation.IntRange;
+import androidx.annotation.Nullable;
+import androidx.media.AudioAttributesCompat;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import androidx.media2.common.SessionPlayer;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.ControlDispatcher;
+import com.google.android.exoplayer2.ExoPlaybackException;
+import com.google.android.exoplayer2.PlaybackParameters;
+import com.google.android.exoplayer2.PlaybackPreparer;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.audio.AudioAttributes;
+import com.google.android.exoplayer2.audio.AudioListener;
+import com.google.android.exoplayer2.util.Assertions;
+import java.util.List;
+
+/**
+ * Wraps an ExoPlayer {@link Player} instance and provides methods and notifies events like those in
+ * the {@link SessionPlayer} API.
+ */
+/* package */ final class PlayerWrapper {
+
+  /** Listener for player wrapper events. */
+  public interface Listener {
+    /**
+     * Called when the player state is changed.
+     *
+     * <p>This method will be called at first if multiple events should be notified at once.
+     */
+    void onPlayerStateChanged(/* @SessionPlayer.PlayerState */ int playerState);
+
+    /** Called when the player is prepared. */
+    void onPrepared(MediaItem mediaItem, int bufferingPercentage);
+
+    /** Called when a seek request has completed. */
+    void onSeekCompleted();
+
+    /** Called when the player rebuffers. */
+    void onBufferingStarted(MediaItem mediaItem);
+
+    /** Called when the player becomes ready again after rebuffering. */
+    void onBufferingEnded(MediaItem mediaItem, int bufferingPercentage);
+
+    /** Called periodically with the player's buffered position as a percentage. */
+    void onBufferingUpdate(MediaItem mediaItem, int bufferingPercentage);
+
+    /** Called when current media item is changed. */
+    void onCurrentMediaItemChanged(MediaItem mediaItem);
+
+    /** Called when playback of the item list has ended. */
+    void onPlaybackEnded();
+
+    /** Called when the player encounters an error. */
+    void onError(@Nullable MediaItem mediaItem);
+
+    /** Called when the playlist is changed */
+    void onPlaylistChanged();
+
+    /** Called when the shuffle mode is changed */
+    void onShuffleModeChanged(int shuffleMode);
+
+    /** Called when the repeat mode is changed */
+    void onRepeatModeChanged(int repeatMode);
+
+    /** Called when the audio attributes is changed */
+    void onAudioAttributesChanged(AudioAttributesCompat audioAttributes);
+
+    /** Called when the playback speed is changed */
+    void onPlaybackSpeedChanged(float playbackSpeed);
+  }
+
+  private static final int POLL_BUFFER_INTERVAL_MS = 1000;
+
+  private final Listener listener;
+  private final PlayerHandler handler;
+  private final Runnable pollBufferRunnable;
+
+  private final Player player;
+  private final PlaylistManager playlistManager;
+  private final PlaybackPreparer playbackPreparer;
+  private final ControlDispatcher controlDispatcher;
+  private final ComponentListener componentListener;
+
+  private boolean prepared;
+  private boolean rebuffering;
+  private int currentWindowIndex;
+
+  /**
+   * Creates a new ExoPlayer wrapper.
+   *
+   * @param listener A listener for player wrapper events.
+   * @param player The player to handle commands
+   * @param playlistManager The playlist manager to handle playlist commands
+   * @param playbackPreparer The playback preparer to prepare
+   * @param controlDispatcher A {@link ControlDispatcher} that should be used for dispatching
+   *     changes to the player.
+   */
+  PlayerWrapper(
+      Listener listener,
+      Player player,
+      PlaylistManager playlistManager,
+      PlaybackPreparer playbackPreparer,
+      ControlDispatcher controlDispatcher) {
+    this.listener = listener;
+    this.player = player;
+    this.playlistManager = playlistManager;
+    this.playbackPreparer = playbackPreparer;
+    this.controlDispatcher = controlDispatcher;
+
+    componentListener = new ComponentListener();
+    player.addListener(componentListener);
+    @Nullable Player.AudioComponent audioComponent = player.getAudioComponent();
+    if (audioComponent != null) {
+      audioComponent.addAudioListener(componentListener);
+    }
+
+    handler = new PlayerHandler(player.getApplicationLooper());
+    pollBufferRunnable = new PollBufferRunnable();
+
+    currentWindowIndex = C.INDEX_UNSET;
+  }
+
+  public boolean setMediaItem(MediaItem mediaItem) {
+    boolean handled = playlistManager.setMediaItem(player, mediaItem);
+    if (handled) {
+      currentWindowIndex = playlistManager.getCurrentMediaItemIndex(player);
+    }
+    return handled;
+  }
+
+  public boolean setPlaylist(List<MediaItem> playlist, @Nullable MediaMetadata metadata) {
+    boolean handled = playlistManager.setPlaylist(player, playlist, metadata);
+    if (handled) {
+      currentWindowIndex = playlistManager.getCurrentMediaItemIndex(player);
+    }
+    return handled;
+  }
+
+  public boolean addPlaylistItem(int index, MediaItem item) {
+    return playlistManager.addPlaylistItem(player, index, item);
+  }
+
+  public boolean removePlaylistItem(@IntRange(from = 0) int index) {
+    return playlistManager.removePlaylistItem(player, index);
+  }
+
+  public boolean replacePlaylistItem(int index, MediaItem item) {
+    return playlistManager.replacePlaylistItem(player, index, item);
+  }
+
+  public boolean skipToPreviousPlaylistItem() {
+    return playlistManager.skipToPreviousPlaylistItem(player, controlDispatcher);
+  }
+
+  public boolean skipToNextPlaylistItem() {
+    return playlistManager.skipToNextPlaylistItem(player, controlDispatcher);
+  }
+
+  public boolean skipToPlaylistItem(@IntRange(from = 0) int index) {
+    return playlistManager.skipToPlaylistItem(player, controlDispatcher, index);
+  }
+
+  public boolean updatePlaylistMetadata(@Nullable MediaMetadata metadata) {
+    return playlistManager.updatePlaylistMetadata(player, metadata);
+  }
+
+  public boolean setRepeatMode(int repeatMode) {
+    return controlDispatcher.dispatchSetRepeatMode(
+        player, Utils.getExoPlayerRepeatMode(repeatMode));
+  }
+
+  public boolean setShuffleMode(int shuffleMode) {
+    return controlDispatcher.dispatchSetShuffleModeEnabled(
+        player, Utils.getExoPlayerShuffleMode(shuffleMode));
+  }
+
+  @Nullable
+  public List<MediaItem> getPlaylist() {
+    return playlistManager.getPlaylist(player);
+  }
+
+  @Nullable
+  public MediaMetadata getPlaylistMetadata() {
+    return playlistManager.getPlaylistMetadata(player);
+  }
+
+  public int getRepeatMode() {
+    return Utils.getRepeatMode(player.getRepeatMode());
+  }
+
+  public int getShuffleMode() {
+    return Utils.getShuffleMode(player.getShuffleModeEnabled());
+  }
+
+  public int getCurrentMediaItemIndex() {
+    return playlistManager.getCurrentMediaItemIndex(player);
+  }
+
+  public int getPreviousMediaItemIndex() {
+    return player.getPreviousWindowIndex();
+  }
+
+  public int getNextMediaItemIndex() {
+    return player.getNextWindowIndex();
+  }
+
+  @Nullable
+  public MediaItem getCurrentMediaItem() {
+    return playlistManager.getCurrentMediaItem(player);
+  }
+
+  public boolean prepare() {
+    if (prepared) {
+      return false;
+    }
+    playbackPreparer.preparePlayback();
+    return true;
+  }
+
+  public boolean play() {
+    if (player.getPlaybackState() == Player.STATE_ENDED) {
+      int currentWindowIndex = playlistManager.getCurrentMediaItemIndex(player);
+      boolean seekHandled =
+          controlDispatcher.dispatchSeekTo(player, currentWindowIndex, /* positionMs= */ 0);
+      if (!seekHandled) {
+        return false;
+      }
+    }
+    boolean playWhenReady = player.getPlayWhenReady();
+    int suppressReason = player.getPlaybackSuppressionReason();
+    if (playWhenReady && suppressReason == Player.PLAYBACK_SUPPRESSION_REASON_NONE) {
+      return false;
+    }
+    return controlDispatcher.dispatchSetPlayWhenReady(player, /* playWhenReady= */ true);
+  }
+
+  public boolean pause() {
+    boolean playWhenReady = player.getPlayWhenReady();
+    int suppressReason = player.getPlaybackSuppressionReason();
+    if (!playWhenReady && suppressReason == Player.PLAYBACK_SUPPRESSION_REASON_NONE) {
+      return false;
+    }
+    return controlDispatcher.dispatchSetPlayWhenReady(player, /* playWhenReady= */ false);
+  }
+
+  public boolean seekTo(long position) {
+    int currentWindowIndex = playlistManager.getCurrentMediaItemIndex(player);
+    return controlDispatcher.dispatchSeekTo(player, currentWindowIndex, position);
+  }
+
+  public long getCurrentPosition() {
+    Assertions.checkState(getState() != SessionPlayer.PLAYER_STATE_IDLE);
+    return Math.max(0, player.getCurrentPosition());
+  }
+
+  public long getDuration() {
+    Assertions.checkState(getState() != SessionPlayer.PLAYER_STATE_IDLE);
+    long duration = player.getDuration();
+    return duration == C.TIME_UNSET ? -1 : duration;
+  }
+
+  public long getBufferedPosition() {
+    Assertions.checkState(getState() != SessionPlayer.PLAYER_STATE_IDLE);
+    return player.getBufferedPosition();
+  }
+
+  /* @SessionPlayer.PlayerState */
+  private int getState() {
+    if (hasError()) {
+      return SessionPlayer.PLAYER_STATE_ERROR;
+    }
+    int state = player.getPlaybackState();
+    boolean playWhenReady = player.getPlayWhenReady();
+    switch (state) {
+      case Player.STATE_IDLE:
+        return SessionPlayer.PLAYER_STATE_IDLE;
+      case Player.STATE_ENDED:
+        return SessionPlayer.PLAYER_STATE_PAUSED;
+      case Player.STATE_BUFFERING:
+      case Player.STATE_READY:
+        return playWhenReady
+            ? SessionPlayer.PLAYER_STATE_PLAYING
+            : SessionPlayer.PLAYER_STATE_PAUSED;
+      default:
+        throw new IllegalStateException();
+    }
+  }
+
+  public boolean setAudioAttributes(AudioAttributesCompat audioAttributes) {
+    Player.AudioComponent audioComponent = Assertions.checkStateNotNull(player.getAudioComponent());
+    audioComponent.setAudioAttributes(
+        Utils.getAudioAttributes(audioAttributes), /* handleAudioFocus= */ true);
+    return true;
+  }
+
+  public AudioAttributesCompat getAudioAttributes() {
+    @Nullable Player.AudioComponent audioComponent = player.getAudioComponent();
+    return Utils.getAudioAttributesCompat(
+        audioComponent != null ? audioComponent.getAudioAttributes() : AudioAttributes.DEFAULT);
+  }
+
+  public boolean setPlaybackSpeed(float playbackSpeed) {
+    player.setPlaybackParameters(new PlaybackParameters(playbackSpeed));
+    return true;
+  }
+
+  public float getPlaybackSpeed() {
+    return player.getPlaybackParameters().speed;
+  }
+
+  public void reset() {
+    controlDispatcher.dispatchStop(player, /* reset= */ true);
+    prepared = false;
+    rebuffering = false;
+  }
+
+  public void close() {
+    handler.removeCallbacks(pollBufferRunnable);
+    player.removeListener(componentListener);
+
+    @Nullable Player.AudioComponent audioComponent = player.getAudioComponent();
+    if (audioComponent != null) {
+      audioComponent.removeAudioListener(componentListener);
+    }
+  }
+
+  public boolean isCurrentMediaItemSeekable() {
+    return getCurrentMediaItem() != null
+        && !player.isPlayingAd()
+        && player.isCurrentWindowSeekable();
+  }
+
+  public boolean canSkipToPlaylistItem() {
+    @Nullable List<MediaItem> playlist = getPlaylist();
+    return playlist != null && playlist.size() > 1;
+  }
+
+  public boolean canSkipToPreviousPlaylistItem() {
+    return player.hasPrevious();
+  }
+
+  public boolean canSkipToNextPlaylistItem() {
+    return player.hasNext();
+  }
+
+  public boolean hasError() {
+    return player.getPlayerError() != null;
+  }
+
+  private void handlePlayWhenReadyChanged() {
+    listener.onPlayerStateChanged(getState());
+  }
+
+  private void handlePlayerStateChanged(@Player.State int state) {
+    if (state == Player.STATE_READY || state == Player.STATE_BUFFERING) {
+      handler.postOrRun(pollBufferRunnable);
+    } else {
+      handler.removeCallbacks(pollBufferRunnable);
+    }
+
+    switch (state) {
+      case Player.STATE_BUFFERING:
+        maybeNotifyBufferingEvents();
+        break;
+      case Player.STATE_READY:
+        maybeNotifyReadyEvents();
+        break;
+      case Player.STATE_ENDED:
+        maybeNotifyEndedEvents();
+        break;
+      case Player.STATE_IDLE:
+        // Do nothing.
+        break;
+      default:
+        throw new IllegalStateException();
+    }
+  }
+
+  private void handlePositionDiscontinuity(@Player.DiscontinuityReason int reason) {
+    int currentWindowIndex = playlistManager.getCurrentMediaItemIndex(player);
+    if (this.currentWindowIndex != currentWindowIndex) {
+      this.currentWindowIndex = currentWindowIndex;
+      MediaItem currentMediaItem =
+          Assertions.checkNotNull(playlistManager.getCurrentMediaItem(player));
+      listener.onCurrentMediaItemChanged(currentMediaItem);
+    } else {
+      listener.onSeekCompleted();
+    }
+  }
+
+  private void handlePlayerError() {
+    listener.onPlayerStateChanged(SessionPlayer.PLAYER_STATE_ERROR);
+    listener.onError(getCurrentMediaItem());
+  }
+
+  private void handleRepeatModeChanged(@Player.RepeatMode int repeatMode) {
+    listener.onRepeatModeChanged(Utils.getRepeatMode(repeatMode));
+  }
+
+  private void handleShuffleMode(boolean shuffleModeEnabled) {
+    listener.onShuffleModeChanged(Utils.getShuffleMode(shuffleModeEnabled));
+  }
+
+  private void handlePlaybackParametersChanged(PlaybackParameters playbackParameters) {
+    listener.onPlaybackSpeedChanged(playbackParameters.speed);
+  }
+
+  private void handleTimelineChanged() {
+    playlistManager.onTimelineChanged(player);
+    listener.onPlaylistChanged();
+  }
+
+  private void handleAudioAttributesChanged(AudioAttributes audioAttributes) {
+    listener.onAudioAttributesChanged(Utils.getAudioAttributesCompat(audioAttributes));
+  }
+
+  private void updateBufferingAndScheduleNextPollBuffer() {
+    MediaItem mediaItem = Assertions.checkNotNull(getCurrentMediaItem());
+    listener.onBufferingUpdate(mediaItem, player.getBufferedPercentage());
+    handler.removeCallbacks(pollBufferRunnable);
+    handler.postDelayed(pollBufferRunnable, POLL_BUFFER_INTERVAL_MS);
+  }
+
+  private void maybeNotifyBufferingEvents() {
+    MediaItem mediaItem = Assertions.checkNotNull(getCurrentMediaItem());
+    if (prepared && !rebuffering) {
+      rebuffering = true;
+      listener.onBufferingStarted(mediaItem);
+    }
+  }
+
+  private void maybeNotifyReadyEvents() {
+    MediaItem mediaItem = Assertions.checkNotNull(getCurrentMediaItem());
+    boolean prepareComplete = !prepared;
+    if (prepareComplete) {
+      prepared = true;
+      handlePositionDiscontinuity(Player.DISCONTINUITY_REASON_PERIOD_TRANSITION);
+      listener.onPlayerStateChanged(SessionPlayer.PLAYER_STATE_PAUSED);
+      listener.onPrepared(mediaItem, player.getBufferedPercentage());
+    }
+    if (rebuffering) {
+      rebuffering = false;
+      listener.onBufferingEnded(mediaItem, player.getBufferedPercentage());
+    }
+  }
+
+  private void maybeNotifyEndedEvents() {
+    if (player.getPlayWhenReady()) {
+      listener.onPlayerStateChanged(SessionPlayer.PLAYER_STATE_PAUSED);
+      listener.onPlaybackEnded();
+      player.setPlayWhenReady(false);
+    }
+  }
+
+  private final class ComponentListener implements Player.EventListener, AudioListener {
+
+    // Player.EventListener implementation.
+
+    @Override
+    public void onPlayWhenReadyChanged(boolean playWhenReady, int reason) {
+      handlePlayWhenReadyChanged();
+    }
+
+    @Override
+    public void onPlaybackStateChanged(@Player.State int state) {
+      handlePlayerStateChanged(state);
+    }
+
+    @Override
+    public void onPositionDiscontinuity(@Player.DiscontinuityReason int reason) {
+      handlePositionDiscontinuity(reason);
+    }
+
+    @Override
+    public void onPlayerError(ExoPlaybackException error) {
+      handlePlayerError();
+    }
+
+    @Override
+    public void onRepeatModeChanged(@Player.RepeatMode int repeatMode) {
+      handleRepeatModeChanged(repeatMode);
+    }
+
+    @Override
+    public void onShuffleModeEnabledChanged(boolean shuffleModeEnabled) {
+      handleShuffleMode(shuffleModeEnabled);
+    }
+
+    @Override
+    public void onPlaybackParametersChanged(PlaybackParameters playbackParameters) {
+      handlePlaybackParametersChanged(playbackParameters);
+    }
+
+    @Override
+    public void onTimelineChanged(Timeline timeline, int reason) {
+      handleTimelineChanged();
+    }
+
+    // AudioListener implementation.
+
+    @Override
+    public void onAudioAttributesChanged(AudioAttributes audioAttributes) {
+      handleAudioAttributesChanged(audioAttributes);
+    }
+  }
+
+  private final class PollBufferRunnable implements Runnable {
+    @Override
+    public void run() {
+      updateBufferingAndScheduleNextPollBuffer();
+    }
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/PlaylistManager.java

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import androidx.annotation.Nullable;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import androidx.media2.common.SessionPlayer;
+import com.google.android.exoplayer2.ControlDispatcher;
+import com.google.android.exoplayer2.Player;
+import java.util.List;
+
+/** Interface that handles playlist edit and navigation operations. */
+public interface PlaylistManager {
+  /**
+   * See {@link SessionPlayer#setPlaylist(List, MediaMetadata)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param playlist A list of {@link MediaItem} objects to set as a play list.
+   * @param metadata The metadata of the playlist.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean setPlaylist(Player player, List<MediaItem> playlist, @Nullable MediaMetadata metadata);
+
+  /**
+   * See {@link SessionPlayer#addPlaylistItem(int, MediaItem)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param index The index of the item you want to add in the playlist.
+   * @param mediaItem The media item you want to add.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean addPlaylistItem(Player player, int index, MediaItem mediaItem);
+
+  /**
+   * See {@link SessionPlayer#removePlaylistItem(int)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param index The index of the item you want to remove in the playlist.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean removePlaylistItem(Player player, int index);
+
+  /**
+   * See {@link SessionPlayer#replacePlaylistItem(int, MediaItem)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param mediaItem The media item you want to replace with.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean replacePlaylistItem(Player player, int index, MediaItem mediaItem);
+
+  /**
+   * See {@link SessionPlayer#setMediaItem(MediaItem)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param mediaItem The media item you want to set.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean setMediaItem(Player player, MediaItem mediaItem);
+
+  /**
+   * See {@link SessionPlayer#updatePlaylistMetadata(MediaMetadata)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param metadata The metadata of the playlist.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean updatePlaylistMetadata(Player player, @Nullable MediaMetadata metadata);
+
+  /**
+   * See {@link SessionPlayer#skipToNextPlaylistItem()}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param controlDispatcher A {@link ControlDispatcher} that should be used for dispatching
+   *     changes to the player.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean skipToNextPlaylistItem(Player player, ControlDispatcher controlDispatcher);
+
+  /**
+   * See {@link SessionPlayer#skipToPreviousPlaylistItem()}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param controlDispatcher A {@link ControlDispatcher} that should be used for dispatching
+   *     changes to the player.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean skipToPreviousPlaylistItem(Player player, ControlDispatcher controlDispatcher);
+
+  /**
+   * See {@link SessionPlayer#skipToPlaylistItem(int)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @param controlDispatcher A {@link ControlDispatcher} that should be used for dispatching
+   *     changes to the player.
+   * @return true if the operation was dispatched. False if suppressed.
+   */
+  boolean skipToPlaylistItem(Player player, ControlDispatcher controlDispatcher, int index);
+
+  /**
+   * See {@link SessionPlayer#getCurrentMediaItemIndex()}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @return The current media item index
+   */
+  int getCurrentMediaItemIndex(Player player);
+
+  /**
+   * See {@link SessionPlayer#getCurrentMediaItem()}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @return The current media item index
+   */
+  @Nullable
+  MediaItem getCurrentMediaItem(Player player);
+
+  /**
+   * See {@link SessionPlayer#setPlaylist(List, MediaMetadata)}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @return The playlist.
+   */
+  @Nullable
+  List<MediaItem> getPlaylist(Player player);
+
+  /**
+   * See {@link SessionPlayer#getPlaylistMetadata()}.
+   *
+   * @param player The player used to build SessionPlayer together.
+   * @return The metadata of the playlist.
+   */
+  @Nullable
+  MediaMetadata getPlaylistMetadata(Player player);
+
+  /**
+   * Called when the player's timeline is changed.
+   *
+   * @param player The player used to build SessionPlayer together.
+   */
+  void onTimelineChanged(Player player);
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/SessionCallback.java

@@ -0,0 +1,384 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import android.os.Bundle;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import androidx.media2.common.Rating;
+import androidx.media2.common.SessionPlayer;
+import androidx.media2.session.MediaSession;
+import androidx.media2.session.SessionCommand;
+import androidx.media2.session.SessionCommandGroup;
+import androidx.media2.session.SessionResult;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.ext.media2.SessionCallbackBuilder.AllowedCommandProvider;
+import com.google.android.exoplayer2.ext.media2.SessionCallbackBuilder.CustomCommandProvider;
+import com.google.android.exoplayer2.ext.media2.SessionCallbackBuilder.DisconnectedCallback;
+import com.google.android.exoplayer2.ext.media2.SessionCallbackBuilder.MediaItemProvider;
+import com.google.android.exoplayer2.ext.media2.SessionCallbackBuilder.PostConnectCallback;
+import com.google.android.exoplayer2.ext.media2.SessionCallbackBuilder.RatingCallback;
+import com.google.android.exoplayer2.ext.media2.SessionCallbackBuilder.SkipCallback;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Log;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+/* package */ class SessionCallback extends MediaSession.SessionCallback {
+  private static final String TAG = "SessionCallback";
+
+  private final SessionPlayer sessionPlayer;
+  private final int fastForwardMs;
+  private final int rewindMs;
+  private final int seekTimeoutMs;
+  private final Set<MediaSession> sessions;
+  private final AllowedCommandProvider allowedCommandProvider;
+  @Nullable private final RatingCallback ratingCallback;
+  @Nullable private final CustomCommandProvider customCommandProvider;
+  @Nullable private final MediaItemProvider mediaItemProvider;
+  @Nullable private final SkipCallback skipCallback;
+  @Nullable private final PostConnectCallback postConnectCallback;
+  @Nullable private final DisconnectedCallback disconnectedCallback;
+  private boolean loggedUnexpectedSessionPlayerWarning;
+
+  public SessionCallback(
+      SessionPlayerConnector sessionPlayerConnector,
+      int fastForwardMs,
+      int rewindMs,
+      int seekTimeoutMs,
+      AllowedCommandProvider allowedCommandProvider,
+      @Nullable RatingCallback ratingCallback,
+      @Nullable CustomCommandProvider customCommandProvider,
+      @Nullable MediaItemProvider mediaItemProvider,
+      @Nullable SkipCallback skipCallback,
+      @Nullable PostConnectCallback postConnectCallback,
+      @Nullable DisconnectedCallback disconnectedCallback) {
+    this.sessionPlayer = sessionPlayerConnector;
+    this.allowedCommandProvider = allowedCommandProvider;
+    this.ratingCallback = ratingCallback;
+    this.customCommandProvider = customCommandProvider;
+    this.mediaItemProvider = mediaItemProvider;
+    this.skipCallback = skipCallback;
+    this.postConnectCallback = postConnectCallback;
+    this.disconnectedCallback = disconnectedCallback;
+    this.fastForwardMs = fastForwardMs;
+    this.rewindMs = rewindMs;
+    this.seekTimeoutMs = seekTimeoutMs;
+    this.sessions = Collections.newSetFromMap(new ConcurrentHashMap<>());
+
+    // Register PlayerCallback and make it to be called before the ListenableFuture set the result.
+    // It help the PlayerCallback to update allowed commands before pended Player APIs are executed.
+    sessionPlayerConnector.registerPlayerCallback(Runnable::run, new PlayerCallback());
+  }
+
+  @Override
+  @Nullable
+  public SessionCommandGroup onConnect(
+      MediaSession session, MediaSession.ControllerInfo controllerInfo) {
+    sessions.add(session);
+    if (!allowedCommandProvider.acceptConnection(session, controllerInfo)) {
+      return null;
+    }
+    SessionCommandGroup baseAllowedCommands = buildAllowedCommands(session, controllerInfo);
+    return allowedCommandProvider.getAllowedCommands(session, controllerInfo, baseAllowedCommands);
+  }
+
+  @Override
+  public void onPostConnect(
+      @NonNull MediaSession session, @NonNull MediaSession.ControllerInfo controller) {
+    if (postConnectCallback != null) {
+      postConnectCallback.onPostConnect(session, controller);
+    }
+  }
+
+  @Override
+  public void onDisconnected(MediaSession session, MediaSession.ControllerInfo controller) {
+    if (session.getConnectedControllers().isEmpty()) {
+      sessions.remove(session);
+    }
+    if (disconnectedCallback != null) {
+      disconnectedCallback.onDisconnected(session, controller);
+    }
+  }
+
+  @Override
+  public int onCommandRequest(
+      MediaSession session, MediaSession.ControllerInfo controller, SessionCommand command) {
+    return allowedCommandProvider.onCommandRequest(session, controller, command);
+  }
+
+  @Override
+  @Nullable
+  public MediaItem onCreateMediaItem(
+      MediaSession session, MediaSession.ControllerInfo controller, String mediaId) {
+    Assertions.checkNotNull(mediaItemProvider);
+    return mediaItemProvider.onCreateMediaItem(session, controller, mediaId);
+  }
+
+  @Override
+  public int onSetRating(
+      MediaSession session, MediaSession.ControllerInfo controller, String mediaId, Rating rating) {
+    if (ratingCallback != null) {
+      return ratingCallback.onSetRating(session, controller, mediaId, rating);
+    }
+    return SessionResult.RESULT_ERROR_NOT_SUPPORTED;
+  }
+
+  @Override
+  public SessionResult onCustomCommand(
+      MediaSession session,
+      MediaSession.ControllerInfo controller,
+      SessionCommand customCommand,
+      @Nullable Bundle args) {
+    if (customCommandProvider != null) {
+      return customCommandProvider.onCustomCommand(session, controller, customCommand, args);
+    }
+    return new SessionResult(SessionResult.RESULT_ERROR_NOT_SUPPORTED, null);
+  }
+
+  @Override
+  public int onFastForward(MediaSession session, MediaSession.ControllerInfo controller) {
+    if (fastForwardMs > 0) {
+      return seekToOffset(fastForwardMs);
+    }
+    return SessionResult.RESULT_ERROR_NOT_SUPPORTED;
+  }
+
+  @Override
+  public int onRewind(MediaSession session, MediaSession.ControllerInfo controller) {
+    if (rewindMs > 0) {
+      return seekToOffset(-rewindMs);
+    }
+    return SessionResult.RESULT_ERROR_NOT_SUPPORTED;
+  }
+
+  @Override
+  public int onSkipBackward(
+      @NonNull MediaSession session, @NonNull MediaSession.ControllerInfo controller) {
+    if (skipCallback != null) {
+      return skipCallback.onSkipBackward(session, controller);
+    }
+    return SessionResult.RESULT_ERROR_NOT_SUPPORTED;
+  }
+
+  @Override
+  public int onSkipForward(
+      @NonNull MediaSession session, @NonNull MediaSession.ControllerInfo controller) {
+    if (skipCallback != null) {
+      return skipCallback.onSkipForward(session, controller);
+    }
+    return SessionResult.RESULT_ERROR_NOT_SUPPORTED;
+  }
+
+  private int seekToOffset(long offsetMs) {
+    long positionMs = sessionPlayer.getCurrentPosition() + offsetMs;
+    long durationMs = sessionPlayer.getDuration();
+    if (durationMs != C.TIME_UNSET) {
+      positionMs = Math.min(positionMs, durationMs);
+    }
+    positionMs = Math.max(positionMs, 0);
+
+    ListenableFuture<SessionPlayer.PlayerResult> result = sessionPlayer.seekTo(positionMs);
+    try {
+      if (seekTimeoutMs <= 0) {
+        return result.get().getResultCode();
+      }
+      return result.get(seekTimeoutMs, TimeUnit.MILLISECONDS).getResultCode();
+    } catch (ExecutionException | InterruptedException | TimeoutException e) {
+      Log.w(TAG, "Failed to get the seeking result", e);
+      return SessionResult.RESULT_ERROR_UNKNOWN;
+    }
+  }
+
+  private SessionCommandGroup buildAllowedCommands(
+      MediaSession session, MediaSession.ControllerInfo controllerInfo) {
+    SessionCommandGroup.Builder build;
+    @Nullable
+    SessionCommandGroup commands =
+        (customCommandProvider != null)
+            ? customCommandProvider.getCustomCommands(session, controllerInfo)
+            : null;
+    if (commands != null) {
+      build = new SessionCommandGroup.Builder(commands);
+    } else {
+      build = new SessionCommandGroup.Builder();
+    }
+
+    build.addAllPredefinedCommands(SessionCommand.COMMAND_VERSION_1);
+    // TODO: Use removeCommand(int) when it's added [Internal: b/142848015].
+    if (mediaItemProvider == null) {
+      build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SET_MEDIA_ITEM));
+      build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SET_PLAYLIST));
+      build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM));
+      build.removeCommand(
+          new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM));
+    }
+    if (ratingCallback == null) {
+      build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_SET_RATING));
+    }
+    if (skipCallback == null) {
+      build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_SKIP_BACKWARD));
+      build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_SKIP_FORWARD));
+    }
+
+    // Apply player's capability.
+    // Check whether the session has unexpectedly changed the player.
+    if (session.getPlayer() instanceof SessionPlayerConnector) {
+      SessionPlayerConnector sessionPlayerConnector = (SessionPlayerConnector) session.getPlayer();
+
+      // Check whether skipTo* works.
+      if (!sessionPlayerConnector.canSkipToPlaylistItem()) {
+        build.removeCommand(
+            new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM));
+      }
+      if (!sessionPlayerConnector.canSkipToPreviousPlaylistItem()) {
+        build.removeCommand(
+            new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM));
+      }
+      if (!sessionPlayerConnector.canSkipToNextPlaylistItem()) {
+        build.removeCommand(
+            new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM));
+      }
+
+      // Check whether seekTo/rewind/fastForward works.
+      if (!sessionPlayerConnector.isCurrentMediaItemSeekable()) {
+        build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SEEK_TO));
+        build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_FAST_FORWARD));
+        build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_REWIND));
+      } else {
+        if (fastForwardMs <= 0) {
+          build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_FAST_FORWARD));
+        }
+        if (rewindMs <= 0) {
+          build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_REWIND));
+        }
+      }
+    } else {
+      if (!loggedUnexpectedSessionPlayerWarning) {
+        // This can happen if MediaSession#updatePlayer() is called.
+        Log.e(TAG, "SessionPlayer isn't a SessionPlayerConnector. Guess the allowed command.");
+        loggedUnexpectedSessionPlayerWarning = true;
+      }
+
+      if (fastForwardMs <= 0) {
+        build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_FAST_FORWARD));
+      }
+      if (rewindMs <= 0) {
+        build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_REWIND));
+      }
+      @Nullable List<MediaItem> playlist = sessionPlayer.getPlaylist();
+      if (playlist == null) {
+        build.removeCommand(
+            new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM));
+        build.removeCommand(
+            new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM));
+        build.removeCommand(
+            new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM));
+      } else {
+        if (playlist.isEmpty()
+            && (sessionPlayer.getRepeatMode() == SessionPlayer.REPEAT_MODE_NONE
+                || sessionPlayer.getRepeatMode() == SessionPlayer.REPEAT_MODE_ONE)) {
+          build.removeCommand(
+              new SessionCommand(
+                  SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM));
+        }
+        if (playlist.size() == sessionPlayer.getCurrentMediaItemIndex() + 1
+            && (sessionPlayer.getRepeatMode() == SessionPlayer.REPEAT_MODE_NONE
+                || sessionPlayer.getRepeatMode() == SessionPlayer.REPEAT_MODE_ONE)) {
+          build.removeCommand(
+              new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM));
+        }
+        if (playlist.size() <= 1) {
+          build.removeCommand(
+              new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM));
+        }
+      }
+    }
+    return build.build();
+  }
+
+  private static boolean isBufferedState(/* @SessionPlayer.BuffState */ int buffState) {
+    return buffState == SessionPlayer.BUFFERING_STATE_BUFFERING_AND_PLAYABLE
+        || buffState == SessionPlayer.BUFFERING_STATE_COMPLETE;
+  }
+
+  private final class PlayerCallback extends SessionPlayer.PlayerCallback {
+    private boolean currentMediaItemBuffered;
+
+    @Override
+    public void onPlaylistChanged(
+        SessionPlayer player, @Nullable List<MediaItem> list, @Nullable MediaMetadata metadata) {
+      updateAllowedCommands();
+    }
+
+    @Override
+    public void onPlayerStateChanged(SessionPlayer player, int playerState) {
+      updateAllowedCommands();
+    }
+
+    @Override
+    public void onRepeatModeChanged(SessionPlayer player, int repeatMode) {
+      updateAllowedCommands();
+    }
+
+    @Override
+    public void onShuffleModeChanged(SessionPlayer player, int shuffleMode) {
+      updateAllowedCommands();
+    }
+
+    @Override
+    public void onCurrentMediaItemChanged(SessionPlayer player, MediaItem item) {
+      currentMediaItemBuffered = isBufferedState(player.getBufferingState());
+      updateAllowedCommands();
+    }
+
+    @Override
+    public void onBufferingStateChanged(
+        SessionPlayer player, @Nullable MediaItem item, int buffState) {
+      if (currentMediaItemBuffered || player.getCurrentMediaItem() != item) {
+        return;
+      }
+      if (isBufferedState(buffState)) {
+        currentMediaItemBuffered = true;
+        updateAllowedCommands();
+      }
+    }
+
+    private void updateAllowedCommands() {
+      for (MediaSession session : sessions) {
+        List<MediaSession.ControllerInfo> connectedControllers = session.getConnectedControllers();
+        for (MediaSession.ControllerInfo controller : connectedControllers) {
+          SessionCommandGroup baseAllowedCommands = buildAllowedCommands(session, controller);
+          SessionCommandGroup allowedCommands =
+              allowedCommandProvider.getAllowedCommands(session, controller, baseAllowedCommands);
+          if (allowedCommands == null) {
+            allowedCommands = new SessionCommandGroup.Builder().build();
+          }
+          session.setAllowedCommands(controller, allowedCommands);
+        }
+      }
+    }
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/SessionCallbackBuilder.java

@@ -0,0 +1,563 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import android.Manifest;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.Settings;
+import android.text.TextUtils;
+import androidx.annotation.Nullable;
+import androidx.media.MediaSessionManager;
+import androidx.media.MediaSessionManager.RemoteUserInfo;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import androidx.media2.common.Rating;
+import androidx.media2.common.SessionPlayer;
+import androidx.media2.common.UriMediaItem;
+import androidx.media2.session.MediaController;
+import androidx.media2.session.MediaSession;
+import androidx.media2.session.MediaSession.ControllerInfo;
+import androidx.media2.session.SessionCommand;
+import androidx.media2.session.SessionCommandGroup;
+import androidx.media2.session.SessionResult;
+import com.google.android.exoplayer2.util.Assertions;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Builds {@link MediaSession.SessionCallback} with various collaborators.
+ *
+ * @see MediaSession.SessionCallback
+ */
+public final class SessionCallbackBuilder {
+  /** Default timeout value for {@link #setSeekTimeoutMs}. */
+  public static final int DEFAULT_SEEK_TIMEOUT_MS = 1_000;
+
+  private final Context context;
+  private final SessionPlayerConnector sessionPlayerConnector;
+  private int fastForwardMs;
+  private int rewindMs;
+  private int seekTimeoutMs;
+  @Nullable private RatingCallback ratingCallback;
+  @Nullable private CustomCommandProvider customCommandProvider;
+  @Nullable private MediaItemProvider mediaItemProvider;
+  @Nullable private AllowedCommandProvider allowedCommandProvider;
+  @Nullable private SkipCallback skipCallback;
+  @Nullable private PostConnectCallback postConnectCallback;
+  @Nullable private DisconnectedCallback disconnectedCallback;
+
+  /** Provides allowed commands for {@link MediaController}. */
+  public interface AllowedCommandProvider {
+    /**
+     * Called to query whether to allow connection from the controller.
+     *
+     * <p>If it returns {@code true} to accept connection, then {@link #getAllowedCommands} will be
+     * immediately followed to return initial allowed command.
+     *
+     * <p>Prefer use {@link PostConnectCallback} for any extra initialization about controller,
+     * where controller is connected and session can send commands to the controller.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller that is requesting
+     *     connect.
+     * @return {@code true} to accept connection. {@code false} otherwise.
+     */
+    boolean acceptConnection(MediaSession session, ControllerInfo controllerInfo);
+
+    /**
+     * Called to query allowed commands in following cases:
+     *
+     * <ul>
+     *   <li>A {@link MediaController} requests to connect, and allowed commands is required to tell
+     *       initial allowed commands.
+     *   <li>Underlying {@link SessionPlayer} state changes, and allowed commands may be updated via
+     *       {@link MediaSession#setAllowedCommands}.
+     * </ul>
+     *
+     * <p>The provided {@code baseAllowedSessionCommand} is built automatically based on the state
+     * of the {@link SessionPlayer}, {@link RatingCallback}, {@link MediaItemProvider}, {@link
+     * CustomCommandProvider}, and {@link SkipCallback} so may be a useful starting point for any
+     * required customizations.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller for which allowed
+     *     commands are being queried.
+     * @param baseAllowedSessionCommand Base allowed session commands for customization.
+     * @return The allowed commands for the controller.
+     * @see MediaSession.SessionCallback#onConnect(MediaSession, ControllerInfo)
+     */
+    SessionCommandGroup getAllowedCommands(
+        MediaSession session,
+        ControllerInfo controllerInfo,
+        SessionCommandGroup baseAllowedSessionCommand);
+
+    /**
+     * Called when a {@link MediaController} has called an API that controls {@link SessionPlayer}
+     * set to the {@link MediaSession}.
+     *
+     * @param session The media session.
+     * @param controllerInfo A {@link ControllerInfo} that needs allowed command update.
+     * @param command A {@link SessionCommand} from the controller.
+     * @return A session result code defined in {@link SessionResult}.
+     * @see MediaSession.SessionCallback#onCommandRequest
+     */
+    int onCommandRequest(
+        MediaSession session, ControllerInfo controllerInfo, SessionCommand command);
+  }
+
+  /** Callback receiving a user rating for a specified media id. */
+  public interface RatingCallback {
+    /**
+     * Called when the specified controller has set a rating for the specified media id.
+     *
+     * @see MediaSession.SessionCallback#onSetRating(MediaSession, MediaSession.ControllerInfo,
+     *     String, Rating)
+     * @see androidx.media2.session.MediaController#setRating(String, Rating)
+     * @return One of the {@link SessionResult} {@code RESULT_*} constants describing the success or
+     *     failure of the operation, for example, {@link SessionResult#RESULT_SUCCESS} if the
+     *     operation succeeded.
+     */
+    int onSetRating(MediaSession session, ControllerInfo controller, String mediaId, Rating rating);
+  }
+
+  /**
+   * Callbacks for querying what custom commands are supported, and for handling a custom command
+   * when a controller sends it.
+   */
+  public interface CustomCommandProvider {
+    /**
+     * Called when a controller has sent a custom command.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller that sent the custom
+     *     command.
+     * @param customCommand A {@link SessionCommand} from the controller.
+     * @param args A {@link Bundle} with the extra argument.
+     * @see MediaSession.SessionCallback#onCustomCommand(MediaSession, MediaSession.ControllerInfo,
+     *     SessionCommand, Bundle)
+     * @see androidx.media2.session.MediaController#sendCustomCommand(SessionCommand, Bundle)
+     */
+    SessionResult onCustomCommand(
+        MediaSession session,
+        ControllerInfo controllerInfo,
+        SessionCommand customCommand,
+        @Nullable Bundle args);
+
+    /**
+     * Returns a {@link SessionCommandGroup} with custom commands to publish to the controller, or
+     * {@code null} if no custom commands should be published.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller that is requesting custom
+     *     commands.
+     * @return The custom commands to publish, or {@code null} if no custom commands should be
+     *     published.
+     */
+    @Nullable
+    SessionCommandGroup getCustomCommands(MediaSession session, ControllerInfo controllerInfo);
+  }
+
+  /** Provides the {@link MediaItem}. */
+  public interface MediaItemProvider {
+    /**
+     * Called when {@link MediaSession.SessionCallback#onCreateMediaItem(MediaSession,
+     * ControllerInfo, String)} is called.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller that has requested to
+     *     create the item.
+     * @return A new {@link MediaItem} that {@link SessionPlayerConnector} can play.
+     * @see MediaSession.SessionCallback#onCreateMediaItem(MediaSession, ControllerInfo, String)
+     * @see androidx.media2.session.MediaController#addPlaylistItem(int, String)
+     * @see androidx.media2.session.MediaController#replacePlaylistItem(int, String)
+     * @see androidx.media2.session.MediaController#setMediaItem(String)
+     * @see androidx.media2.session.MediaController#setPlaylist(List, MediaMetadata)
+     */
+    @Nullable
+    MediaItem onCreateMediaItem(
+        MediaSession session, ControllerInfo controllerInfo, String mediaId);
+  }
+
+  /** Callback receiving skip backward and skip forward. */
+  public interface SkipCallback {
+    /**
+     * Called when the specified controller has sent skip backward.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller that has requested to
+     *     skip backward.
+     * @see MediaSession.SessionCallback#onSkipBackward(MediaSession, MediaSession.ControllerInfo)
+     * @see MediaController#skipBackward()
+     * @return One of the {@link SessionResult} {@code RESULT_*} constants describing the success or
+     *     failure of the operation, for example, {@link SessionResult#RESULT_SUCCESS} if the
+     *     operation succeeded.
+     */
+    int onSkipBackward(MediaSession session, ControllerInfo controllerInfo);
+
+    /**
+     * Called when the specified controller has sent skip forward.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller that has requested to
+     *     skip forward.
+     * @see MediaSession.SessionCallback#onSkipForward(MediaSession, MediaSession.ControllerInfo)
+     * @see MediaController#skipForward()
+     * @return One of the {@link SessionResult} {@code RESULT_*} constants describing the success or
+     *     failure of the operation, for example, {@link SessionResult#RESULT_SUCCESS} if the
+     *     operation succeeded.
+     */
+    int onSkipForward(MediaSession session, ControllerInfo controllerInfo);
+  }
+
+  /** Callback for handling extra initialization after the connection. */
+  public interface PostConnectCallback {
+    /**
+     * Called after the specified controller is connected, and you need extra initialization.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the controller that just connected.
+     * @see MediaSession.SessionCallback#onPostConnect(MediaSession, ControllerInfo)
+     */
+    void onPostConnect(MediaSession session, MediaSession.ControllerInfo controllerInfo);
+  }
+
+  /** Callback for handling controller disconnection. */
+  public interface DisconnectedCallback {
+    /**
+     * Called when the specified controller is disconnected.
+     *
+     * @param session The media session.
+     * @param controllerInfo The {@link ControllerInfo} for the disconnected controller.
+     * @see MediaSession.SessionCallback#onDisconnected(MediaSession, ControllerInfo)
+     */
+    void onDisconnected(MediaSession session, MediaSession.ControllerInfo controllerInfo);
+  }
+
+  /**
+   * Default implementation of {@link AllowedCommandProvider} that behaves as follows:
+   *
+   * <ul>
+   *   <li>Accepts connection requests from controller if any of the following conditions are met:
+   *       <ul>
+   *         <li>Controller is in the same package as the session.
+   *         <li>Controller is allowed via {@link #setTrustedPackageNames(List)}.
+   *         <li>Controller has package name {@link RemoteUserInfo#LEGACY_CONTROLLER}. See {@link
+   *             ControllerInfo#getPackageName() package name limitation} for details.
+   *         <li>Controller is trusted (i.e. has MEDIA_CONTENT_CONTROL permission or has enabled
+   *             notification manager).
+   *       </ul>
+   *   <li>Allows all commands that the current player can handle.
+   *   <li>Accepts all command requests for allowed commands.
+   * </ul>
+   *
+   * <p>Note: this implementation matches the behavior of the ExoPlayer MediaSession extension and
+   * {@link android.support.v4.media.session.MediaSessionCompat}.
+   */
+  public static final class DefaultAllowedCommandProvider implements AllowedCommandProvider {
+    private final Context context;
+    private final List<String> trustedPackageNames;
+
+    public DefaultAllowedCommandProvider(Context context) {
+      this.context = context;
+      trustedPackageNames = new ArrayList<>();
+    }
+
+    @Override
+    public boolean acceptConnection(MediaSession session, ControllerInfo controllerInfo) {
+      return TextUtils.equals(controllerInfo.getPackageName(), context.getPackageName())
+          || TextUtils.equals(controllerInfo.getPackageName(), RemoteUserInfo.LEGACY_CONTROLLER)
+          || trustedPackageNames.contains(controllerInfo.getPackageName())
+          || isTrusted(controllerInfo);
+    }
+
+    @Override
+    public SessionCommandGroup getAllowedCommands(
+        MediaSession session,
+        ControllerInfo controllerInfo,
+        SessionCommandGroup baseAllowedSessionCommands) {
+      return baseAllowedSessionCommands;
+    }
+
+    @Override
+    public int onCommandRequest(
+        MediaSession session, ControllerInfo controllerInfo, SessionCommand command) {
+      return SessionResult.RESULT_SUCCESS;
+    }
+
+    /**
+     * Sets the package names from which the session will accept incoming connections.
+     *
+     * <p>Apps that have {@code android.Manifest.permission.MEDIA_CONTENT_CONTROL}, packages listed
+     * in enabled_notification_listeners and the current package are always trusted, even if they
+     * are not specified here.
+     *
+     * @param packageNames Package names from which the session will accept incoming connections.
+     * @see MediaSession.SessionCallback#onConnect(MediaSession, MediaSession.ControllerInfo)
+     * @see MediaSessionManager#isTrustedForMediaControl(RemoteUserInfo)
+     */
+    public void setTrustedPackageNames(@Nullable List<String> packageNames) {
+      trustedPackageNames.clear();
+      if (packageNames != null && !packageNames.isEmpty()) {
+        trustedPackageNames.addAll(packageNames);
+      }
+    }
+
+    // TODO: Replace with ControllerInfo#isTrusted() when it's unhidden [Internal: b/142835448].
+    private boolean isTrusted(MediaSession.ControllerInfo controllerInfo) {
+      // Check whether the controller has granted MEDIA_CONTENT_CONTROL.
+      if (context
+              .getPackageManager()
+              .checkPermission(
+                  Manifest.permission.MEDIA_CONTENT_CONTROL, controllerInfo.getPackageName())
+          == PackageManager.PERMISSION_GRANTED) {
+        return true;
+      }
+
+      // Check whether the app has an enabled notification listener.
+      String enabledNotificationListeners =
+          Settings.Secure.getString(context.getContentResolver(), "enabled_notification_listeners");
+      if (!TextUtils.isEmpty(enabledNotificationListeners)) {
+        String[] components = enabledNotificationListeners.split(":");
+        for (String componentString : components) {
+          @Nullable ComponentName component = ComponentName.unflattenFromString(componentString);
+          if (component != null) {
+            if (component.getPackageName().equals(controllerInfo.getPackageName())) {
+              return true;
+            }
+          }
+        }
+      }
+      return false;
+    }
+  }
+
+  /**
+   * Default implementation of {@link MediaItemProvider} that assumes the media id is a URI string.
+   */
+  public static final class DefaultMediaItemProvider implements MediaItemProvider {
+    @Override
+    @Nullable
+    public MediaItem onCreateMediaItem(
+        MediaSession session, ControllerInfo controllerInfo, String mediaId) {
+      if (TextUtils.isEmpty(mediaId)) {
+        return null;
+      }
+      try {
+        new URI(mediaId);
+      } catch (URISyntaxException e) {
+        // Ignore if mediaId isn't a URI.
+        return null;
+      }
+      MediaMetadata metadata =
+          new MediaMetadata.Builder()
+              .putString(MediaMetadata.METADATA_KEY_MEDIA_ID, mediaId)
+              .build();
+      return new UriMediaItem.Builder(Uri.parse(mediaId)).setMetadata(metadata).build();
+    }
+  }
+
+  /**
+   * Creates a new builder.
+   *
+   * <p>The builder uses the following default values:
+   *
+   * <ul>
+   *   <li>{@link AllowedCommandProvider}: {@link DefaultAllowedCommandProvider}
+   *   <li>Seek timeout: {@link #DEFAULT_SEEK_TIMEOUT_MS}
+   *   <li>
+   * </ul>
+   *
+   * Unless stated above, {@code null} or {@code 0} would be used to disallow relevant features.
+   *
+   * @param context A context.
+   * @param sessionPlayerConnector A session player connector to handle incoming calls from the
+   *     controller.
+   */
+  public SessionCallbackBuilder(Context context, SessionPlayerConnector sessionPlayerConnector) {
+    this.context = Assertions.checkNotNull(context);
+    this.sessionPlayerConnector = Assertions.checkNotNull(sessionPlayerConnector);
+    this.seekTimeoutMs = DEFAULT_SEEK_TIMEOUT_MS;
+  }
+
+  /**
+   * Sets the {@link RatingCallback} to handle user ratings.
+   *
+   * @param ratingCallback A rating callback.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onSetRating(MediaSession, ControllerInfo, String, Rating)
+   * @see androidx.media2.session.MediaController#setRating(String, Rating)
+   */
+  public SessionCallbackBuilder setRatingCallback(@Nullable RatingCallback ratingCallback) {
+    this.ratingCallback = ratingCallback;
+    return this;
+  }
+
+  /**
+   * Sets the {@link CustomCommandProvider} to handle incoming custom commands.
+   *
+   * @param customCommandProvider A custom command provider.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onCustomCommand(MediaSession, ControllerInfo, SessionCommand,
+   *     Bundle)
+   * @see androidx.media2.session.MediaController#sendCustomCommand(SessionCommand, Bundle)
+   */
+  public SessionCallbackBuilder setCustomCommandProvider(
+      @Nullable CustomCommandProvider customCommandProvider) {
+    this.customCommandProvider = customCommandProvider;
+    return this;
+  }
+
+  /**
+   * Sets the {@link MediaItemProvider} that will convert media ids to {@link MediaItem MediaItems}.
+   *
+   * @param mediaItemProvider The media item provider.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onCreateMediaItem(MediaSession, ControllerInfo, String)
+   * @see androidx.media2.session.MediaController#addPlaylistItem(int, String)
+   * @see androidx.media2.session.MediaController#replacePlaylistItem(int, String)
+   * @see androidx.media2.session.MediaController#setMediaItem(String)
+   * @see androidx.media2.session.MediaController#setPlaylist(List, MediaMetadata)
+   */
+  public SessionCallbackBuilder setMediaItemProvider(
+      @Nullable MediaItemProvider mediaItemProvider) {
+    this.mediaItemProvider = mediaItemProvider;
+    return this;
+  }
+
+  /**
+   * Sets the {@link AllowedCommandProvider} to provide allowed commands for controllers.
+   *
+   * @param allowedCommandProvider A allowed command provider.
+   * @return This builder.
+   */
+  public SessionCallbackBuilder setAllowedCommandProvider(
+      @Nullable AllowedCommandProvider allowedCommandProvider) {
+    this.allowedCommandProvider = allowedCommandProvider;
+    return this;
+  }
+
+  /**
+   * Sets the {@link SkipCallback} to handle skip backward and skip forward.
+   *
+   * @param skipCallback The skip callback.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onSkipBackward(MediaSession, ControllerInfo)
+   * @see MediaSession.SessionCallback#onSkipForward(MediaSession, ControllerInfo)
+   * @see MediaController#skipBackward()
+   * @see MediaController#skipForward()
+   */
+  public SessionCallbackBuilder setSkipCallback(@Nullable SkipCallback skipCallback) {
+    this.skipCallback = skipCallback;
+    return this;
+  }
+
+  /**
+   * Sets the {@link PostConnectCallback} to handle extra initialization after the connection.
+   *
+   * @param postConnectCallback The post connect callback.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onPostConnect(MediaSession, ControllerInfo)
+   */
+  public SessionCallbackBuilder setPostConnectCallback(
+      @Nullable PostConnectCallback postConnectCallback) {
+    this.postConnectCallback = postConnectCallback;
+    return this;
+  }
+
+  /**
+   * Sets the {@link DisconnectedCallback} to handle cleaning up controller.
+   *
+   * @param disconnectedCallback The disconnected callback.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onDisconnected(MediaSession, ControllerInfo)
+   */
+  public SessionCallbackBuilder setDisconnectedCallback(
+      @Nullable DisconnectedCallback disconnectedCallback) {
+    this.disconnectedCallback = disconnectedCallback;
+    return this;
+  }
+
+  /**
+   * Sets the rewind increment in milliseconds.
+   *
+   * @param rewindMs The rewind increment in milliseconds. A non-positive value will cause the
+   *     rewind to be disabled.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onRewind(MediaSession, MediaSession.ControllerInfo)
+   * @see #setSeekTimeoutMs(int)
+   */
+  public SessionCallbackBuilder setRewindIncrementMs(int rewindMs) {
+    this.rewindMs = rewindMs;
+    return this;
+  }
+
+  /**
+   * Sets the fast forward increment in milliseconds.
+   *
+   * @param fastForwardMs The fast forward increment in milliseconds. A non-positive value will
+   *     cause the fast forward to be disabled.
+   * @return This builder.
+   * @see MediaSession.SessionCallback#onFastForward(MediaSession, MediaSession.ControllerInfo)
+   * @see #setSeekTimeoutMs(int)
+   */
+  public SessionCallbackBuilder setFastForwardIncrementMs(int fastForwardMs) {
+    this.fastForwardMs = fastForwardMs;
+    return this;
+  }
+
+  /**
+   * Sets the timeout in milliseconds for fast forward and rewind operations, or {@code 0} for no
+   * timeout. If a timeout is set, controllers will receive an error if the session's call to {@link
+   * SessionPlayer#seekTo} takes longer than this amount of time.
+   *
+   * @param seekTimeoutMs A timeout for {@link SessionPlayer#seekTo}. A non-positive value will wait
+   *     forever.
+   * @return This builder.
+   */
+  public SessionCallbackBuilder setSeekTimeoutMs(int seekTimeoutMs) {
+    this.seekTimeoutMs = seekTimeoutMs;
+    return this;
+  }
+
+  /**
+   * Builds {@link MediaSession.SessionCallback}.
+   *
+   * @return A new callback for a media session.
+   */
+  public MediaSession.SessionCallback build() {
+    return new SessionCallback(
+        sessionPlayerConnector,
+        fastForwardMs,
+        rewindMs,
+        seekTimeoutMs,
+        allowedCommandProvider == null
+            ? new DefaultAllowedCommandProvider(context)
+            : allowedCommandProvider,
+        ratingCallback,
+        customCommandProvider,
+        mediaItemProvider,
+        skipCallback,
+        postConnectCallback,
+        disconnectedCallback);
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/SessionPlayerConnector.java

@@ -0,0 +1,764 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import android.util.Log;
+import androidx.annotation.FloatRange;
+import androidx.annotation.GuardedBy;
+import androidx.annotation.IntRange;
+import androidx.annotation.Nullable;
+import androidx.core.util.ObjectsCompat;
+import androidx.core.util.Pair;
+import androidx.media.AudioAttributesCompat;
+import androidx.media2.common.FileMediaItem;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import androidx.media2.common.SessionPlayer;
+import com.google.android.exoplayer2.ControlDispatcher;
+import com.google.android.exoplayer2.DefaultControlDispatcher;
+import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
+import com.google.android.exoplayer2.PlaybackPreparer;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executor;
+import org.checkerframework.checker.initialization.qual.Initialized;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
+
+/**
+ * An implementation of {@link SessionPlayer} that wraps a given ExoPlayer {@link Player} instance.
+ *
+ * <h3>Ownership</h3>
+ *
+ * <p>{@code SessionPlayerConnector} takes ownership of the provided ExoPlayer {@link Player}
+ * instance between when it's constructed and when it's {@link #close() closed}. No other components
+ * should interact with the wrapped player (otherwise, unexpected event callbacks from the wrapped
+ * player may put the session player in an inconsistent state).
+ *
+ * <p>Call {@link SessionPlayer#close()} when the {@code SessionPlayerConnector} is no longer needed
+ * to regain ownership of the wrapped player. It is the caller's responsibility to release the
+ * wrapped player via {@link Player#release()}.
+ *
+ * <h3>Threading model</h3>
+ *
+ * <p>Internally this implementation posts operations to and receives callbacks on the thread
+ * associated with {@link Player#getApplicationLooper()}, so it is important not to block this
+ * thread. In particular, when awaiting the result of an asynchronous session player operation, apps
+ * should generally use {@link ListenableFuture#addListener(Runnable, Executor)} to be notified of
+ * completion, rather than calling the blocking {@link ListenableFuture#get()} method.
+ */
+public final class SessionPlayerConnector extends SessionPlayer {
+
+  static {
+    ExoPlayerLibraryInfo.registerModule("goog.exo.media2");
+  }
+
+  private static final String TAG = "SessionPlayerConnector";
+
+  private static final int END_OF_PLAYLIST = -1;
+  private final Object stateLock = new Object();
+
+  private final PlayerHandler taskHandler;
+  private final Executor taskHandlerExecutor;
+  private final PlayerWrapper player;
+  private final PlayerCommandQueue playerCommandQueue;
+
+  @GuardedBy("stateLock")
+  private final Map<MediaItem, Integer> mediaItemToBuffState = new HashMap<>();
+
+  @GuardedBy("stateLock")
+  /* @PlayerState */
+  private int state;
+
+  @GuardedBy("stateLock")
+  private boolean closed;
+
+  // Should be only accessed on the executor, which is currently single-threaded.
+  @Nullable private MediaItem currentMediaItem;
+  @Nullable private List<MediaItem> currentPlaylist;
+
+  /**
+   * Creates an instance using {@link DefaultControlDispatcher} to dispatch player commands.
+   *
+   * @param player The player to wrap.
+   * @param playlistManager The {@link PlaylistManager}.
+   * @param playbackPreparer The {@link PlaybackPreparer}.
+   */
+  public SessionPlayerConnector(
+      Player player, PlaylistManager playlistManager, PlaybackPreparer playbackPreparer) {
+    this(player, playlistManager, playbackPreparer, new DefaultControlDispatcher());
+  }
+
+  /**
+   * Creates an instance using the provided {@link ControlDispatcher} to dispatch player commands.
+   *
+   * @param player The player to wrap.
+   * @param playlistManager The {@link PlaylistManager}.
+   * @param playbackPreparer The {@link PlaybackPreparer}.
+   * @param controlDispatcher The {@link ControlDispatcher}.
+   */
+  public SessionPlayerConnector(
+      Player player,
+      PlaylistManager playlistManager,
+      PlaybackPreparer playbackPreparer,
+      ControlDispatcher controlDispatcher) {
+    Assertions.checkNotNull(player);
+    Assertions.checkNotNull(playlistManager);
+    Assertions.checkNotNull(playbackPreparer);
+    Assertions.checkNotNull(controlDispatcher);
+
+    state = PLAYER_STATE_IDLE;
+    taskHandler = new PlayerHandler(player.getApplicationLooper());
+    taskHandlerExecutor = taskHandler::postOrRun;
+    ExoPlayerWrapperListener playerListener = new ExoPlayerWrapperListener();
+    PlayerWrapper playerWrapper =
+        new PlayerWrapper(
+            playerListener, player, playlistManager, playbackPreparer, controlDispatcher);
+    this.player = playerWrapper;
+    playerCommandQueue = new PlayerCommandQueue(this.player, taskHandler);
+
+    @SuppressWarnings("assignment.type.incompatible")
+    @Initialized
+    SessionPlayerConnector initializedThis = this;
+    initializedThis.<Void>runPlayerCallableBlocking(
+        /* callable= */ () -> {
+          playerWrapper.reset();
+          return null;
+        });
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> play() {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_PLAY, /* command= */ () -> player.play());
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> pause() {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_PAUSE, /* command= */ () -> player.pause());
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> prepare() {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_PREPARE, /* command= */ () -> player.prepare());
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> seekTo(long position) {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_SEEK_TO,
+        /* command= */ () -> player.seekTo(position),
+        /* tag= */ position);
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> setPlaybackSpeed(
+      @FloatRange(from = 0.0f, to = Float.MAX_VALUE, fromInclusive = false) float playbackSpeed) {
+    Assertions.checkArgument(playbackSpeed > 0f);
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_SET_SPEED,
+        /* command= */ () -> player.setPlaybackSpeed(playbackSpeed));
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> setAudioAttributes(AudioAttributesCompat attr) {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_SET_AUDIO_ATTRIBUTES,
+        /* command= */ () -> player.setAudioAttributes(Assertions.checkNotNull(attr)));
+  }
+
+  @Override
+  /* @PlayerState */
+  public int getPlayerState() {
+    synchronized (stateLock) {
+      return state;
+    }
+  }
+
+  @Override
+  public long getCurrentPosition() {
+    long position =
+        runPlayerCallableBlocking(
+            /* callable= */ player::getCurrentPosition,
+            /* defaultValueWhenException= */ UNKNOWN_TIME);
+    return position >= 0 ? position : UNKNOWN_TIME;
+  }
+
+  @Override
+  public long getDuration() {
+    long position =
+        runPlayerCallableBlocking(
+            /* callable= */ player::getDuration, /* defaultValueWhenException= */ UNKNOWN_TIME);
+    return position >= 0 ? position : UNKNOWN_TIME;
+  }
+
+  @Override
+  public long getBufferedPosition() {
+    long position =
+        runPlayerCallableBlocking(
+            /* callable= */ player::getBufferedPosition,
+            /* defaultValueWhenException= */ UNKNOWN_TIME);
+    return position >= 0 ? position : UNKNOWN_TIME;
+  }
+
+  @Override
+  /* @BuffState */
+  public int getBufferingState() {
+    @Nullable
+    MediaItem mediaItem =
+        this.<@NullableType MediaItem>runPlayerCallableBlocking(
+            /* callable= */ player::getCurrentMediaItem, /* defaultValueWhenException= */ null);
+    if (mediaItem == null) {
+      return BUFFERING_STATE_UNKNOWN;
+    }
+    @Nullable Integer buffState;
+    synchronized (stateLock) {
+      buffState = mediaItemToBuffState.get(mediaItem);
+    }
+    return buffState == null ? BUFFERING_STATE_UNKNOWN : buffState;
+  }
+
+  @Override
+  @FloatRange(from = 0.0f, to = Float.MAX_VALUE, fromInclusive = false)
+  public float getPlaybackSpeed() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::getPlaybackSpeed, /* defaultValueWhenException= */ 1.0f);
+  }
+
+  @Override
+  @Nullable
+  public AudioAttributesCompat getAudioAttributes() {
+    return runPlayerCallableBlockingWithNullOnException(/* callable= */ player::getAudioAttributes);
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> setMediaItem(MediaItem item) {
+    Assertions.checkNotNull(item);
+    Assertions.checkArgument(!(item instanceof FileMediaItem));
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_SET_MEDIA_ITEM, () -> player.setMediaItem(item));
+    result.addListener(this::handlePlaylistChangedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> setPlaylist(
+      final List<MediaItem> playlist, @Nullable MediaMetadata metadata) {
+    Assertions.checkNotNull(playlist);
+    Assertions.checkArgument(!playlist.isEmpty());
+    for (int i = 0; i < playlist.size(); i++) {
+      MediaItem item = playlist.get(i);
+      Assertions.checkNotNull(item);
+      Assertions.checkArgument(!(item instanceof FileMediaItem));
+      for (int j = 0; j < i; j++) {
+        Assertions.checkArgument(
+            item != playlist.get(j),
+            "playlist shouldn't contain duplicated item, index=" + i + " vs index=" + j);
+      }
+    }
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_SET_PLAYLIST,
+            /* command= */ () -> player.setPlaylist(playlist, metadata));
+    result.addListener(this::handlePlaylistChangedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> addPlaylistItem(int index, MediaItem item) {
+    Assertions.checkArgument(index >= 0);
+    Assertions.checkNotNull(item);
+    Assertions.checkArgument(!(item instanceof FileMediaItem));
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM,
+            /* command= */ () -> player.addPlaylistItem(index, item));
+    result.addListener(this::handlePlaylistChangedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> removePlaylistItem(@IntRange(from = 0) int index) {
+    Assertions.checkArgument(index >= 0);
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_REMOVE_PLAYLIST_ITEM,
+            /* command= */ () -> player.removePlaylistItem(index));
+    result.addListener(this::handlePlaylistChangedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> replacePlaylistItem(int index, MediaItem item) {
+    Assertions.checkArgument(index >= 0);
+    Assertions.checkNotNull(item);
+    Assertions.checkArgument(!(item instanceof FileMediaItem));
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM,
+            /* command= */ () -> player.replacePlaylistItem(index, item));
+    result.addListener(this::handlePlaylistChangedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> skipToPreviousPlaylistItem() {
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_SKIP_TO_PREVIOUS_PLAYLIST_ITEM,
+            /* command= */ player::skipToPreviousPlaylistItem);
+    result.addListener(this::notifySkipToCompletedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> skipToNextPlaylistItem() {
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_SKIP_TO_NEXT_PLAYLIST_ITEM,
+            /* command= */ player::skipToNextPlaylistItem);
+    result.addListener(this::notifySkipToCompletedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> skipToPlaylistItem(@IntRange(from = 0) int index) {
+    Assertions.checkArgument(index >= 0);
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_SKIP_TO_PLAYLIST_ITEM,
+            /* command= */ () -> player.skipToPlaylistItem(index));
+    result.addListener(this::notifySkipToCompletedOnHandler, taskHandlerExecutor);
+    return result;
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> updatePlaylistMetadata(@Nullable MediaMetadata metadata) {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_UPDATE_LIST_METADATA,
+        /* command= */ () -> {
+          boolean handled = player.updatePlaylistMetadata(metadata);
+          if (handled) {
+            notifySessionPlayerCallback(
+                callback ->
+                    callback.onPlaylistMetadataChanged(SessionPlayerConnector.this, metadata));
+          }
+          return handled;
+        });
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> setRepeatMode(int repeatMode) {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_SET_REPEAT_MODE,
+        /* command= */ () -> player.setRepeatMode(repeatMode));
+  }
+
+  @Override
+  public ListenableFuture<PlayerResult> setShuffleMode(int shuffleMode) {
+    return playerCommandQueue.addCommand(
+        PlayerCommandQueue.COMMAND_CODE_PLAYER_SET_SHUFFLE_MODE,
+        /* command= */ () -> player.setShuffleMode(shuffleMode));
+  }
+
+  @Override
+  @Nullable
+  public List<MediaItem> getPlaylist() {
+    return runPlayerCallableBlockingWithNullOnException(/* callable= */ player::getPlaylist);
+  }
+
+  @Override
+  @Nullable
+  public MediaMetadata getPlaylistMetadata() {
+    return runPlayerCallableBlockingWithNullOnException(
+        /* callable= */ player::getPlaylistMetadata);
+  }
+
+  @Override
+  public int getRepeatMode() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::getRepeatMode, /* defaultValueWhenException= */ REPEAT_MODE_NONE);
+  }
+
+  @Override
+  public int getShuffleMode() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::getShuffleMode, /* defaultValueWhenException= */ SHUFFLE_MODE_NONE);
+  }
+
+  @Override
+  @Nullable
+  public MediaItem getCurrentMediaItem() {
+    return runPlayerCallableBlockingWithNullOnException(
+        /* callable= */ player::getCurrentMediaItem);
+  }
+
+  @Override
+  public int getCurrentMediaItemIndex() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::getCurrentMediaItemIndex,
+        /* defaultValueWhenException= */ END_OF_PLAYLIST);
+  }
+
+  @Override
+  public int getPreviousMediaItemIndex() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::getPreviousMediaItemIndex,
+        /* defaultValueWhenException= */ END_OF_PLAYLIST);
+  }
+
+  @Override
+  public int getNextMediaItemIndex() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::getNextMediaItemIndex,
+        /* defaultValueWhenException= */ END_OF_PLAYLIST);
+  }
+
+  // TODO(b/147706139): Call super.close() after updating media2-common to 1.1.0
+  @SuppressWarnings("MissingSuperCall")
+  @Override
+  public void close() {
+    synchronized (stateLock) {
+      if (closed) {
+        return;
+      }
+      closed = true;
+    }
+    reset();
+
+    this.<Void>runPlayerCallableBlockingInternal(
+        /* callable= */ () -> {
+          player.close();
+          return null;
+        });
+  }
+
+  // SessionPlayerConnector-specific functions.
+
+  /**
+   * Returns whether the current media item is seekable.
+   *
+   * @return {@code true} if supported. {@code false} otherwise.
+   */
+  /* package */ boolean isCurrentMediaItemSeekable() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::isCurrentMediaItemSeekable, /* defaultValueWhenException= */ false);
+  }
+
+  /**
+   * Returns whether {@link #skipToPlaylistItem(int)} is supported.
+   *
+   * @return {@code true} if supported. {@code false} otherwise.
+   */
+  /* package */ boolean canSkipToPlaylistItem() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::canSkipToPlaylistItem, /* defaultValueWhenException= */ false);
+  }
+
+  /**
+   * Returns whether {@link #skipToPreviousPlaylistItem()} is supported.
+   *
+   * @return {@code true} if supported. {@code false} otherwise.
+   */
+  /* package */ boolean canSkipToPreviousPlaylistItem() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::canSkipToPreviousPlaylistItem,
+        /* defaultValueWhenException= */ false);
+  }
+
+  /**
+   * Returns whether {@link #skipToNextPlaylistItem()} is supported.
+   *
+   * @return {@code true} if supported. {@code false} otherwise.
+   */
+  /* package */ boolean canSkipToNextPlaylistItem() {
+    return runPlayerCallableBlocking(
+        /* callable= */ player::canSkipToNextPlaylistItem, /* defaultValueWhenException= */ false);
+  }
+
+  /**
+   * Resets {@link SessionPlayerConnector} to its uninitialized state if not closed. After calling
+   * this method, you will have to initialize it again by setting the media item and calling {@link
+   * #prepare()}.
+   *
+   * <p>Note that if the player is closed, there is no way to reuse the instance.
+   */
+  private void reset() {
+    // Cancel the pending commands.
+    playerCommandQueue.reset();
+    synchronized (stateLock) {
+      state = PLAYER_STATE_IDLE;
+      mediaItemToBuffState.clear();
+    }
+    this.<Void>runPlayerCallableBlockingInternal(
+        /* callable= */ () -> {
+          player.reset();
+          return null;
+        });
+  }
+
+  private void setState(/* @PlayerState */ int state) {
+    boolean needToNotify = false;
+    synchronized (stateLock) {
+      if (this.state != state) {
+        this.state = state;
+        needToNotify = true;
+      }
+    }
+    if (needToNotify) {
+      notifySessionPlayerCallback(
+          callback -> callback.onPlayerStateChanged(SessionPlayerConnector.this, state));
+    }
+  }
+
+  private void setBufferingState(MediaItem item, /* @BuffState */ int state) {
+    @Nullable Integer previousState;
+    synchronized (stateLock) {
+      previousState = mediaItemToBuffState.put(item, state);
+    }
+    if (previousState == null || previousState != state) {
+      notifySessionPlayerCallback(
+          callback -> callback.onBufferingStateChanged(SessionPlayerConnector.this, item, state));
+    }
+  }
+
+  private void notifySessionPlayerCallback(SessionPlayerCallbackNotifier notifier) {
+    synchronized (stateLock) {
+      if (closed) {
+        return;
+      }
+    }
+    List<Pair<SessionPlayer.PlayerCallback, Executor>> callbacks = getCallbacks();
+    for (Pair<SessionPlayer.PlayerCallback, Executor> pair : callbacks) {
+      SessionPlayer.PlayerCallback callback = Assertions.checkNotNull(pair.first);
+      Executor executor = Assertions.checkNotNull(pair.second);
+      executor.execute(() -> notifier.callCallback(callback));
+    }
+  }
+
+  private void handlePlaylistChangedOnHandler() {
+    List<MediaItem> currentPlaylist = player.getPlaylist();
+    boolean notifyCurrentPlaylist = !ObjectsCompat.equals(this.currentPlaylist, currentPlaylist);
+    this.currentPlaylist = currentPlaylist;
+    MediaMetadata playlistMetadata = player.getPlaylistMetadata();
+
+    MediaItem currentMediaItem = player.getCurrentMediaItem();
+    boolean notifyCurrentMediaItem = !ObjectsCompat.equals(this.currentMediaItem, currentMediaItem);
+    this.currentMediaItem = currentMediaItem;
+
+    if (!notifyCurrentMediaItem && !notifyCurrentPlaylist) {
+      return;
+    }
+    notifySessionPlayerCallback(
+        callback -> {
+          if (notifyCurrentPlaylist) {
+            callback.onPlaylistChanged(
+                SessionPlayerConnector.this, currentPlaylist, playlistMetadata);
+          }
+          if (notifyCurrentMediaItem) {
+            Assertions.checkNotNull(
+                currentMediaItem, "PlaylistManager#currentMediaItem() cannot be changed to null");
+            callback.onCurrentMediaItemChanged(SessionPlayerConnector.this, currentMediaItem);
+          }
+        });
+  }
+
+  private void notifySkipToCompletedOnHandler() {
+    MediaItem currentMediaItem = Assertions.checkNotNull(player.getCurrentMediaItem());
+    if (ObjectsCompat.equals(this.currentMediaItem, currentMediaItem)) {
+      return;
+    }
+    this.currentMediaItem = currentMediaItem;
+    notifySessionPlayerCallback(
+        callback ->
+            callback.onCurrentMediaItemChanged(SessionPlayerConnector.this, currentMediaItem));
+  }
+
+  private <T> T runPlayerCallableBlocking(Callable<T> callable) {
+    synchronized (stateLock) {
+      Assertions.checkState(!closed);
+    }
+    return runPlayerCallableBlockingInternal(callable);
+  }
+
+  private <T> T runPlayerCallableBlockingInternal(Callable<T> callable) {
+    SettableFuture<T> future = SettableFuture.create();
+    boolean success =
+        taskHandler.postOrRun(
+            () -> {
+              try {
+                future.set(callable.call());
+              } catch (Throwable e) {
+                future.setException(e);
+              }
+            });
+    Assertions.checkState(success);
+    boolean wasInterrupted = false;
+    try {
+      while (true) {
+        try {
+          return future.get();
+        } catch (InterruptedException e) {
+          // We always wait for player calls to return.
+          wasInterrupted = true;
+        } catch (ExecutionException e) {
+          @Nullable Throwable cause = e.getCause();
+          Log.e(TAG, "Internal player error", new RuntimeException(cause));
+          throw new IllegalStateException(cause);
+        }
+      }
+    } finally {
+      if (wasInterrupted) {
+        Thread.currentThread().interrupt();
+      }
+    }
+  }
+
+  @Nullable
+  private <T> T runPlayerCallableBlockingWithNullOnException(Callable<@NullableType T> callable) {
+    try {
+      return runPlayerCallableBlocking(callable);
+    } catch (Exception e) {
+      return null;
+    }
+  }
+
+  private <T> T runPlayerCallableBlocking(Callable<T> callable, T defaultValueWhenException) {
+    try {
+      return runPlayerCallableBlocking(callable);
+    } catch (Exception e) {
+      return defaultValueWhenException;
+    }
+  }
+
+  private interface SessionPlayerCallbackNotifier {
+    void callCallback(SessionPlayer.PlayerCallback callback);
+  }
+
+  private final class ExoPlayerWrapperListener implements PlayerWrapper.Listener {
+    @Override
+    public void onPlayerStateChanged(int playerState) {
+      setState(playerState);
+      if (playerState == PLAYER_STATE_PLAYING) {
+        playerCommandQueue.notifyCommandCompleted(PlayerCommandQueue.COMMAND_CODE_PLAYER_PLAY);
+      } else if (playerState == PLAYER_STATE_PAUSED) {
+        playerCommandQueue.notifyCommandCompleted(PlayerCommandQueue.COMMAND_CODE_PLAYER_PAUSE);
+      }
+    }
+
+    @Override
+    public void onPrepared(MediaItem mediaItem, int bufferingPercentage) {
+      Assertions.checkNotNull(mediaItem);
+
+      if (bufferingPercentage >= 100) {
+        setBufferingState(mediaItem, BUFFERING_STATE_COMPLETE);
+      } else {
+        setBufferingState(mediaItem, BUFFERING_STATE_BUFFERING_AND_PLAYABLE);
+      }
+      playerCommandQueue.notifyCommandCompleted(PlayerCommandQueue.COMMAND_CODE_PLAYER_PREPARE);
+    }
+
+    @Override
+    public void onSeekCompleted() {
+      notifySessionPlayerCallback(
+          callback -> callback.onSeekCompleted(SessionPlayerConnector.this, getCurrentPosition()));
+    }
+
+    @Override
+    public void onBufferingStarted(MediaItem mediaItem) {
+      setBufferingState(mediaItem, BUFFERING_STATE_BUFFERING_AND_STARVED);
+    }
+
+    @Override
+    public void onBufferingUpdate(MediaItem mediaItem, int bufferingPercentage) {
+      if (bufferingPercentage >= 100) {
+        setBufferingState(mediaItem, BUFFERING_STATE_COMPLETE);
+      }
+    }
+
+    @Override
+    public void onBufferingEnded(MediaItem mediaItem, int bufferingPercentage) {
+      if (bufferingPercentage >= 100) {
+        setBufferingState(mediaItem, BUFFERING_STATE_COMPLETE);
+      } else {
+        setBufferingState(mediaItem, BUFFERING_STATE_BUFFERING_AND_PLAYABLE);
+      }
+    }
+
+    @Override
+    public void onCurrentMediaItemChanged(MediaItem mediaItem) {
+      if (ObjectsCompat.equals(currentMediaItem, mediaItem)) {
+        return;
+      }
+      currentMediaItem = mediaItem;
+      notifySessionPlayerCallback(
+          callback -> callback.onCurrentMediaItemChanged(SessionPlayerConnector.this, mediaItem));
+    }
+
+    @Override
+    public void onPlaybackEnded() {
+      notifySessionPlayerCallback(
+          callback -> callback.onPlaybackCompleted(SessionPlayerConnector.this));
+    }
+
+    @Override
+    public void onError(@Nullable MediaItem mediaItem) {
+      playerCommandQueue.notifyCommandError();
+      if (mediaItem != null) {
+        setBufferingState(mediaItem, BUFFERING_STATE_UNKNOWN);
+      }
+    }
+
+    @Override
+    public void onPlaylistChanged() {
+      handlePlaylistChangedOnHandler();
+    }
+
+    @Override
+    public void onShuffleModeChanged(int shuffleMode) {
+      notifySessionPlayerCallback(
+          callback -> callback.onShuffleModeChanged(SessionPlayerConnector.this, shuffleMode));
+    }
+
+    @Override
+    public void onRepeatModeChanged(int repeatMode) {
+      notifySessionPlayerCallback(
+          callback -> callback.onRepeatModeChanged(SessionPlayerConnector.this, repeatMode));
+    }
+
+    @Override
+    public void onPlaybackSpeedChanged(float playbackSpeed) {
+      notifySessionPlayerCallback(
+          callback -> callback.onPlaybackSpeedChanged(SessionPlayerConnector.this, playbackSpeed));
+    }
+
+    @Override
+    public void onAudioAttributesChanged(AudioAttributesCompat audioAttributes) {
+      notifySessionPlayerCallback(
+          callback ->
+              callback.onAudioAttributesChanged(SessionPlayerConnector.this, audioAttributes));
+    }
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/SettableFuture.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.ext.media2;
+
+import androidx.concurrent.futures.CallbackToFutureAdapter;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * A replacement of com.google.common.util.concurrent.SettableFuture with CallbackToFutureAdapter to
+ * avoid the dependency on Guava.
+ */
+@SuppressWarnings("ShouldNotSubclass")
+/* package */ class SettableFuture<V> implements ListenableFuture<V> {
+  static <V> SettableFuture<V> create() {
+    return new SettableFuture<>();
+  }
+
+  private final ListenableFuture<V> future;
+  private final CallbackToFutureAdapter.Completer<V> completer;
+
+  SettableFuture() {
+    AtomicReference<CallbackToFutureAdapter.Completer<V>> completerRef = new AtomicReference<>();
+    future =
+        CallbackToFutureAdapter.getFuture(
+            completer -> {
+              completerRef.set(completer);
+              return null;
+            });
+    completer = Assertions.checkNotNull(completerRef.get());
+  }
+
+  @Override
+  public void addListener(Runnable listener, Executor executor) {
+    future.addListener(listener, executor);
+  }
+
+  @Override
+  public boolean cancel(boolean mayInterruptIfRunning) {
+    return future.cancel(mayInterruptIfRunning);
+  }
+
+  @Override
+  public boolean isCancelled() {
+    return future.isCancelled();
+  }
+
+  @Override
+  public boolean isDone() {
+    return future.isDone();
+  }
+
+  @Override
+  public V get() throws ExecutionException, InterruptedException {
+    return future.get();
+  }
+
+  @Override
+  public V get(long timeout, TimeUnit unit)
+      throws ExecutionException, InterruptedException, TimeoutException {
+    return future.get(timeout, unit);
+  }
+
+  void set(V value) {
+    completer.set(value);
+  }
+
+  void setException(Throwable throwable) {
+    completer.setException(throwable);
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/TimelinePlaylistManager.java

@@ -0,0 +1,332 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import android.content.Context;
+import android.util.Log;
+import androidx.annotation.Nullable;
+import androidx.media2.common.CallbackMediaItem;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.MediaMetadata;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.ControlDispatcher;
+import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.source.ClippingMediaSource;
+import com.google.android.exoplayer2.source.ConcatenatingMediaSource;
+import com.google.android.exoplayer2.source.MediaSource;
+import com.google.android.exoplayer2.upstream.DataSource;
+import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Util;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A default {@link PlaylistManager} implementation based on {@link ConcatenatingMediaSource} that
+ * maps a {@link MediaItem} in the playlist to a {@link MediaSource}.
+ *
+ * <p>When it's used, {@link Player}'s Timeline shouldn't be changed directly, and should be only
+ * changed via {@link TimelinePlaylistManager}. If it's not, internal playlist would be out of sync
+ * with the actual {@link Timeline}. If you need to change Timeline directly, build your own {@link
+ * PlaylistManager} instead.
+ */
+public class TimelinePlaylistManager implements PlaylistManager {
+  private static final String TAG = "TimelinePlaylistManager";
+
+  private final MediaSourceFactory sourceFactory;
+  private final ConcatenatingMediaSource concatenatingMediaSource;
+  private final List<MediaItem> playlist;
+  @Nullable private MediaMetadata playlistMetadata;
+  private boolean loggedUnexpectedTimelineChanges;
+
+  /** Factory to create {@link MediaSource}s. */
+  public interface MediaSourceFactory {
+    /**
+     * Creates a {@link MediaSource} for the given {@link MediaItem}.
+     *
+     * @param mediaItem The {@link MediaItem} to create a media source for.
+     * @return A {@link MediaSource} or {@code null} if no source can be created for the given
+     *     description.
+     */
+    @Nullable
+    MediaSource createMediaSource(MediaItem mediaItem);
+  }
+
+  /**
+   * Default implementation of the {@link MediaSourceFactory}.
+   *
+   * <p>This doesn't support the {@link androidx.media2.common.FileMediaItem}.
+   */
+  public static final class DefaultMediaSourceFactory implements MediaSourceFactory {
+    private final Context context;
+    private final DataSource.Factory dataSourceFactory;
+
+    /**
+     * Default constructor with {@link DefaultDataSourceFactory}.
+     *
+     * @param context The context.
+     */
+    public DefaultMediaSourceFactory(Context context) {
+      this(
+          context,
+          new DefaultDataSourceFactory(
+              context, Util.getUserAgent(context, ExoPlayerLibraryInfo.VERSION_SLASHY)));
+    }
+
+    /**
+     * Default constructor with {@link DataSource.Factory}.
+     *
+     * @param context The context.
+     * @param dataSourceFactory The dataSourceFactory to create {@link MediaSource} from {@link
+     *     MediaItem}.
+     */
+    public DefaultMediaSourceFactory(Context context, DataSource.Factory dataSourceFactory) {
+      this.context = Assertions.checkNotNull(context);
+      this.dataSourceFactory = Assertions.checkNotNull(dataSourceFactory);
+    }
+
+    @Override
+    public MediaSource createMediaSource(MediaItem mediaItem) {
+      // Create a source for the item.
+      MediaSource mediaSource =
+          Utils.createUnclippedMediaSource(context, dataSourceFactory, mediaItem);
+
+      // Apply clipping if needed.
+      long startPosition = mediaItem.getStartPosition();
+      long endPosition = mediaItem.getEndPosition();
+      if (startPosition != 0L || endPosition != MediaItem.POSITION_UNKNOWN) {
+        if (endPosition == MediaItem.POSITION_UNKNOWN) {
+          endPosition = C.TIME_END_OF_SOURCE;
+        }
+        // Disable the initial discontinuity to give seamless transitions to clips.
+        mediaSource =
+            new ClippingMediaSource(
+                mediaSource,
+                C.msToUs(startPosition),
+                C.msToUs(endPosition),
+                /* enableInitialDiscontinuity= */ false,
+                /* allowDynamicClippingUpdates= */ false,
+                /* relativeToDefaultPosition= */ true);
+      }
+
+      return mediaSource;
+    }
+  }
+
+  /**
+   * Creates a new {@link TimelinePlaylistManager} with the {@link DefaultMediaSourceFactory}.
+   *
+   * @param context The context.
+   * @param concatenatingMediaSource The {@link ConcatenatingMediaSource} to manipulate.
+   */
+  public TimelinePlaylistManager(
+      Context context, ConcatenatingMediaSource concatenatingMediaSource) {
+    this(concatenatingMediaSource, new DefaultMediaSourceFactory(context));
+  }
+
+  /**
+   * Creates a new {@link TimelinePlaylistManager} with a given mediaSourceFactory.
+   *
+   * @param concatenatingMediaSource The {@link ConcatenatingMediaSource} to manipulate.
+   * @param sourceFactory The {@link MediaSourceFactory} to build media sources.
+   */
+  public TimelinePlaylistManager(
+      ConcatenatingMediaSource concatenatingMediaSource, MediaSourceFactory sourceFactory) {
+    this.concatenatingMediaSource = concatenatingMediaSource;
+    this.sourceFactory = sourceFactory;
+    this.playlist = new ArrayList<>();
+  }
+
+  @Override
+  public boolean setPlaylist(
+      Player player, List<MediaItem> playlist, @Nullable MediaMetadata metadata) {
+    // Check for duplication.
+    for (int i = 0; i < playlist.size(); i++) {
+      MediaItem mediaItem = playlist.get(i);
+      Assertions.checkArgument(playlist.indexOf(mediaItem) == i);
+    }
+    for (MediaItem mediaItem : this.playlist) {
+      if (!playlist.contains(mediaItem)) {
+        releaseMediaItem(mediaItem);
+      }
+    }
+    this.playlist.clear();
+    this.playlist.addAll(playlist);
+    this.playlistMetadata = metadata;
+
+    concatenatingMediaSource.clear();
+
+    List<MediaSource> mediaSources = new ArrayList<>();
+    for (int i = 0; i < playlist.size(); i++) {
+      MediaItem mediaItem = playlist.get(i);
+      MediaSource mediaSource = createMediaSource(mediaItem);
+      mediaSources.add(mediaSource);
+    }
+    concatenatingMediaSource.addMediaSources(mediaSources);
+    return true;
+  }
+
+  @Override
+  public boolean addPlaylistItem(Player player, int index, MediaItem mediaItem) {
+    Assertions.checkArgument(!playlist.contains(mediaItem));
+    index = Util.constrainValue(index, 0, playlist.size());
+
+    playlist.add(index, mediaItem);
+    MediaSource mediaSource = createMediaSource(mediaItem);
+    concatenatingMediaSource.addMediaSource(index, mediaSource);
+    return true;
+  }
+
+  @Override
+  public boolean removePlaylistItem(Player player, int index) {
+    MediaItem mediaItemToRemove = playlist.remove(index);
+    releaseMediaItem(mediaItemToRemove);
+    concatenatingMediaSource.removeMediaSource(index);
+    return true;
+  }
+
+  @Override
+  public boolean replacePlaylistItem(Player player, int index, MediaItem mediaItem) {
+    Assertions.checkArgument(!playlist.contains(mediaItem));
+    index = Util.constrainValue(index, 0, playlist.size());
+
+    MediaItem mediaItemToRemove = playlist.get(index);
+    playlist.set(index, mediaItem);
+    releaseMediaItem(mediaItemToRemove);
+
+    MediaSource mediaSourceToAdd = createMediaSource(mediaItem);
+    concatenatingMediaSource.removeMediaSource(index);
+    concatenatingMediaSource.addMediaSource(index, mediaSourceToAdd);
+    return true;
+  }
+
+  @Override
+  public boolean setMediaItem(Player player, MediaItem mediaItem) {
+    // TODO(jaewan): Distinguish setMediaItem(item) and setPlaylist({item})
+    List<MediaItem> playlist = new ArrayList<>();
+    playlist.add(mediaItem);
+    return setPlaylist(player, playlist, /* metadata */ null);
+  }
+
+  @Override
+  public boolean updatePlaylistMetadata(Player player, @Nullable MediaMetadata metadata) {
+    this.playlistMetadata = metadata;
+    return true;
+  }
+
+  @Override
+  public boolean skipToNextPlaylistItem(Player player, ControlDispatcher controlDispatcher) {
+    Timeline timeline = player.getCurrentTimeline();
+    Assertions.checkState(!timeline.isEmpty());
+    int nextWindowIndex = player.getNextWindowIndex();
+    if (nextWindowIndex != C.INDEX_UNSET) {
+      return controlDispatcher.dispatchSeekTo(player, nextWindowIndex, C.TIME_UNSET);
+    }
+    return false;
+  }
+
+  @Override
+  public boolean skipToPreviousPlaylistItem(Player player, ControlDispatcher controlDispatcher) {
+    Timeline timeline = player.getCurrentTimeline();
+    Assertions.checkState(!timeline.isEmpty());
+    int previousWindowIndex = player.getPreviousWindowIndex();
+    if (previousWindowIndex != C.INDEX_UNSET) {
+      return controlDispatcher.dispatchSeekTo(player, previousWindowIndex, C.TIME_UNSET);
+    }
+    return false;
+  }
+
+  @Override
+  public boolean skipToPlaylistItem(Player player, ControlDispatcher controlDispatcher, int index) {
+    Timeline timeline = player.getCurrentTimeline();
+    Assertions.checkState(!timeline.isEmpty());
+    // Use checkState() instead of checkIndex() for throwing IllegalStateException.
+    // checkIndex() throws IndexOutOfBoundsException which maps the RESULT_ERROR_BAD_VALUE
+    // but RESULT_ERROR_INVALID_STATE with IllegalStateException is expected here.
+    Assertions.checkState(0 <= index && index < timeline.getWindowCount());
+    int windowIndex = player.getCurrentWindowIndex();
+    if (windowIndex != index) {
+      return controlDispatcher.dispatchSeekTo(player, index, C.TIME_UNSET);
+    }
+    return false;
+  }
+
+  @Override
+  public int getCurrentMediaItemIndex(Player player) {
+    return playlist.isEmpty() ? C.INDEX_UNSET : player.getCurrentWindowIndex();
+  }
+
+  @Override
+  @Nullable
+  public MediaItem getCurrentMediaItem(Player player) {
+    int index = getCurrentMediaItemIndex(player);
+    return (index != C.INDEX_UNSET) ? playlist.get(index) : null;
+  }
+
+  @Override
+  public List<MediaItem> getPlaylist(Player player) {
+    return new ArrayList<>(playlist);
+  }
+
+  @Override
+  @Nullable
+  public MediaMetadata getPlaylistMetadata(Player player) {
+    return playlistMetadata;
+  }
+
+  @Override
+  public void onTimelineChanged(Player player) {
+    checkTimelineWindowCountEqualsToPlaylistSize(player);
+  }
+
+  private void releaseMediaItem(MediaItem mediaItem) {
+    try {
+      if (mediaItem instanceof CallbackMediaItem) {
+        ((CallbackMediaItem) mediaItem).getDataSourceCallback().close();
+      }
+    } catch (IOException e) {
+      Log.w(TAG, "Error releasing media item " + mediaItem, e);
+    }
+  }
+
+  private MediaSource createMediaSource(MediaItem mediaItem) {
+    return Assertions.checkNotNull(
+        sourceFactory.createMediaSource(mediaItem),
+        "createMediaSource() failed, mediaItem=" + mediaItem);
+  }
+
+  // Check whether Timeline's window count matches with the playlist size, and leave log for
+  // mismatch. It's to check whether the Timeline and playlist are out of sync or not at the best
+  // effort.
+  private void checkTimelineWindowCountEqualsToPlaylistSize(Player player) {
+    if (player.getPlaybackState() == Player.STATE_IDLE) {
+      // Cannot do check in STATE_IDLE, because Timeline isn't available.
+      return;
+    }
+    Timeline timeline = player.getCurrentTimeline();
+    if ((playlist == null && timeline.getWindowCount() == 1)
+        || (playlist != null && playlist.size() == timeline.getWindowCount())) {
+      return;
+    }
+    if (!loggedUnexpectedTimelineChanges) {
+      Log.w(TAG, "Timeline is unexpectedly changed. Playlist can be out of sync.");
+      loggedUnexpectedTimelineChanges = true;
+    }
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/Utils.java

@@ -0,0 +1,200 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ext.media2;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.net.Uri;
+import android.text.TextUtils;
+import androidx.annotation.Nullable;
+import androidx.media.AudioAttributesCompat;
+import androidx.media2.common.CallbackMediaItem;
+import androidx.media2.common.MediaItem;
+import androidx.media2.common.SessionPlayer;
+import androidx.media2.common.UriMediaItem;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.audio.AudioAttributes;
+import com.google.android.exoplayer2.extractor.DefaultExtractorsFactory;
+import com.google.android.exoplayer2.extractor.ExtractorsFactory;
+import com.google.android.exoplayer2.extractor.ts.AdtsExtractor;
+import com.google.android.exoplayer2.source.MediaSource;
+import com.google.android.exoplayer2.source.MediaSourceFactory;
+import com.google.android.exoplayer2.source.ProgressiveMediaSource;
+import com.google.android.exoplayer2.upstream.DataSource;
+import com.google.android.exoplayer2.upstream.RawResourceDataSource;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Util;
+
+/**
+ * Utility methods for the media2 extension (primarily for translating between the media2 and
+ * ExoPlayer {@link Player} APIs).
+ */
+/* package */ final class Utils {
+
+  private static final ExtractorsFactory sExtractorsFactory =
+      new DefaultExtractorsFactory()
+          .setAdtsExtractorFlags(AdtsExtractor.FLAG_ENABLE_CONSTANT_BITRATE_SEEKING);
+
+  /**
+   * Returns an ExoPlayer media source for the given media item. The given {@link MediaItem} is set
+   * as the tag of the source.
+   */
+  public static MediaSource createUnclippedMediaSource(
+      Context context, DataSource.Factory dataSourceFactory, MediaItem mediaItem) {
+    if (mediaItem instanceof UriMediaItem) {
+      Uri uri = ((UriMediaItem) mediaItem).getUri();
+      if (ContentResolver.SCHEME_ANDROID_RESOURCE.equals(uri.getScheme())) {
+        String path = Assertions.checkNotNull(uri.getPath());
+        int resourceIdentifier;
+        if (uri.getPathSegments().size() == 1 && uri.getPathSegments().get(0).matches("\\d+")) {
+          resourceIdentifier = Integer.parseInt(uri.getPathSegments().get(0));
+        } else {
+          if (path.startsWith("/")) {
+            path = path.substring(1);
+          }
+          @Nullable String host = uri.getHost();
+          String resourceName = (TextUtils.isEmpty(host) ? "" : (host + ":")) + path;
+          resourceIdentifier =
+              context.getResources().getIdentifier(resourceName, "raw", context.getPackageName());
+        }
+        Assertions.checkState(resourceIdentifier != 0);
+        uri = RawResourceDataSource.buildRawResourceUri(resourceIdentifier);
+      }
+      return createMediaSource(uri, dataSourceFactory, /* tag= */ mediaItem);
+    } else if (mediaItem instanceof CallbackMediaItem) {
+      CallbackMediaItem callbackMediaItem = (CallbackMediaItem) mediaItem;
+      dataSourceFactory =
+          DataSourceCallbackDataSource.getFactory(callbackMediaItem.getDataSourceCallback());
+      return new ProgressiveMediaSource.Factory(dataSourceFactory, sExtractorsFactory)
+          .setTag(mediaItem)
+          .createMediaSource(Uri.EMPTY);
+    } else {
+      throw new IllegalStateException();
+    }
+  }
+
+  /** Returns ExoPlayer audio attributes for the given audio attributes. */
+  public static AudioAttributes getAudioAttributes(AudioAttributesCompat audioAttributesCompat) {
+    return new AudioAttributes.Builder()
+        .setContentType(audioAttributesCompat.getContentType())
+        .setFlags(audioAttributesCompat.getFlags())
+        .setUsage(audioAttributesCompat.getUsage())
+        .build();
+  }
+
+  /** Returns audio attributes for the given ExoPlayer audio attributes. */
+  public static AudioAttributesCompat getAudioAttributesCompat(AudioAttributes audioAttributes) {
+    return new AudioAttributesCompat.Builder()
+        .setContentType(audioAttributes.contentType)
+        .setFlags(audioAttributes.flags)
+        .setUsage(audioAttributes.usage)
+        .build();
+  }
+
+  /** Returns the SimpleExoPlayer's shuffle mode for the given shuffle mode. */
+  public static boolean getExoPlayerShuffleMode(int shuffleMode) {
+    switch (shuffleMode) {
+      case SessionPlayer.SHUFFLE_MODE_ALL:
+      case SessionPlayer.SHUFFLE_MODE_GROUP:
+        return true;
+      case SessionPlayer.SHUFFLE_MODE_NONE:
+        return false;
+      default:
+        throw new IllegalArgumentException();
+    }
+  }
+
+  /** Returns the shuffle mode for the given ExoPlayer's shuffle mode */
+  public static int getShuffleMode(boolean exoPlayerShuffleMode) {
+    return exoPlayerShuffleMode ? SessionPlayer.SHUFFLE_MODE_ALL : SessionPlayer.SHUFFLE_MODE_NONE;
+  }
+
+  /** Returns the ExoPlayer's repeat mode for the given repeat mode. */
+  @Player.RepeatMode
+  public static int getExoPlayerRepeatMode(int repeatMode) {
+    switch (repeatMode) {
+      case SessionPlayer.REPEAT_MODE_ALL:
+      case SessionPlayer.REPEAT_MODE_GROUP:
+        return Player.REPEAT_MODE_ALL;
+      case SessionPlayer.REPEAT_MODE_ONE:
+        return Player.REPEAT_MODE_ONE;
+      case SessionPlayer.REPEAT_MODE_NONE:
+        return Player.REPEAT_MODE_OFF;
+      default:
+        throw new IllegalArgumentException();
+    }
+  }
+
+  /** Returns the repeat mode for the given SimpleExoPlayer's repeat mode. */
+  public static int getRepeatMode(@Player.RepeatMode int exoPlayerRepeatMode) {
+    switch (exoPlayerRepeatMode) {
+      case Player.REPEAT_MODE_ALL:
+        return SessionPlayer.REPEAT_MODE_ALL;
+      case Player.REPEAT_MODE_ONE:
+        return SessionPlayer.REPEAT_MODE_ONE;
+      case Player.REPEAT_MODE_OFF:
+        return SessionPlayer.REPEAT_MODE_NONE;
+      default:
+        throw new IllegalArgumentException();
+    }
+  }
+
+  private static MediaSource createMediaSource(
+      Uri uri, DataSource.Factory dataSourceFactory, Object tag) {
+    // TODO: Deduplicate with DefaultMediaSource once MediaItem support in ExoPlayer has been
+    // released. See [Internal: b/150857202].
+    @Nullable Class<? extends MediaSourceFactory> factoryClazz = null;
+    try {
+      // LINT.IfChange
+      switch (Util.inferContentType(uri)) {
+        case C.TYPE_DASH:
+          factoryClazz =
+              Class.forName("com.google.android.exoplayer2.source.dash.DashMediaSource$Factory")
+                  .asSubclass(MediaSourceFactory.class);
+          break;
+        case C.TYPE_HLS:
+          factoryClazz =
+              Class.forName("com.google.android.exoplayer2.source.hls.HlsMediaSource$Factory")
+                  .asSubclass(MediaSourceFactory.class);
+          break;
+        case C.TYPE_SS:
+          factoryClazz =
+              Class.forName(
+                      "com.google.android.exoplayer2.source.smoothstreaming.SsMediaSource$Factory")
+                  .asSubclass(MediaSourceFactory.class);
+          break;
+        case C.TYPE_OTHER:
+        default:
+          break;
+      }
+      if (factoryClazz != null) {
+        MediaSourceFactory mediaSourceFactory =
+            factoryClazz.getConstructor(DataSource.Factory.class).newInstance(dataSourceFactory);
+        factoryClazz.getMethod("setTag", Object.class).invoke(mediaSourceFactory, tag);
+        return mediaSourceFactory.createMediaSource(uri);
+      }
+      // LINT.ThenChange(../../../../../../../../../proguard-rules.txt)
+    } catch (Exception e) {
+      // Expected if the app was built without the corresponding module.
+    }
+    return new ProgressiveMediaSource.Factory(dataSourceFactory).setTag(tag).createMediaSource(uri);
+  }
+
+  private Utils() {
+    // Prevent instantiation.
+  }
+}

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.ext.media2;
+
+import com.google.android.exoplayer2.util.NonNullApi;

extensions/media2/src/main/proguard-rules.txt

@@ -0,0 +1 @@
+../../proguard-rules.txt