Migrate BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS to Media3

PiperOrigin-RevId: 490376734

libraries/session/src/main/java/androidx/media3/session/MediaConstants.java

@@ -389,12 +389,31 @@ public final class MediaConstants {
    *
    * @see MediaLibrarySession.Callback#onGetLibraryRoot(MediaLibrarySession,
    *     MediaSession.ControllerInfo, LibraryParams)
+   * @see MediaBrowser#getLibraryRoot(LibraryParams)
    * @see LibraryParams#extras
    */
   @UnstableApi
   public static final String EXTRAS_KEY_ROOT_CHILDREN_LIMIT =
       androidx.media.utils.MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_LIMIT;
 
+  /**
+   * {@link Bundle} key used in {@link LibraryParams#extras} passed to {@link
+   * MediaLibrarySession.Callback#onGetLibraryRoot(MediaLibrarySession, MediaSession.ControllerInfo,
+   * LibraryParams)} to indicate whether only browsable media items are supported as children of the
+   * root node by the {@link MediaBrowser}. If true, root children that are not browsable may be
+   * omitted or made less discoverable.
+   *
+   * <p>TYPE: boolean.
+   *
+   * @see MediaLibrarySession.Callback#onGetLibraryRoot(MediaLibrarySession,
+   *     MediaSession.ControllerInfo, LibraryParams)
+   * @see MediaBrowser#getLibraryRoot(LibraryParams)
+   * @see LibraryParams#extras
+   */
+  @UnstableApi
+  public static final String EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY =
+      "androidx.media3.session.LibraryParams.Extras.KEY_ROOT_CHILDREN_BROWSABLE_ONLY";
+
   /**
    * {@link Bundle} key used in {@link LibraryParams#extras} passed by the {@link MediaBrowser} as
    * root hints to {@link MediaLibrarySession.Callback#onGetLibraryRoot(MediaLibrarySession,

libraries/session/src/main/java/androidx/media3/session/MediaUtils.java

@@ -16,6 +16,7 @@
 package androidx.media3.session;
 
 import static android.support.v4.media.session.MediaSessionCompat.FLAG_HANDLES_QUEUE_COMMANDS;
+import static androidx.media.utils.MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS;
 import static androidx.media3.common.Player.COMMAND_ADJUST_DEVICE_VOLUME;
 import static androidx.media3.common.Player.COMMAND_CHANGE_MEDIA_ITEMS;
 import static androidx.media3.common.Player.COMMAND_GET_CURRENT_MEDIA_ITEM;
@@ -38,6 +39,7 @@ import static androidx.media3.common.Player.COMMAND_STOP;
 import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Util.castNonNull;
 import static androidx.media3.common.util.Util.constrainValue;
+import static androidx.media3.session.MediaConstants.EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY;
 import static java.lang.Math.max;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
@@ -996,6 +998,15 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
     }
     try {
       legacyBundle.setClassLoader(context.getClassLoader());
+      int supportedChildrenFlags =
+          legacyBundle.getInt(
+              BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS, /* defaultValue= */ -1);
+      if (supportedChildrenFlags >= 0) {
+        legacyBundle.remove(BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS);
+        legacyBundle.putBoolean(
+            EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY,
+            supportedChildrenFlags == MediaBrowserCompat.MediaItem.FLAG_BROWSABLE);
+      }
       return new LibraryParams.Builder()
           .setExtras(legacyBundle)
           .setRecent(legacyBundle.getBoolean(BrowserRoot.EXTRA_RECENT))
@@ -1015,6 +1026,18 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
       return null;
     }
     Bundle rootHints = new Bundle(params.extras);
+    if (params.extras.containsKey(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY)) {
+      boolean browsableChildrenSupported =
+          params.extras.getBoolean(
+              EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY, /* defaultValue= */ false);
+      rootHints.remove(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY);
+      rootHints.putInt(
+          BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS,
+          browsableChildrenSupported
+              ? MediaBrowserCompat.MediaItem.FLAG_BROWSABLE
+              : MediaBrowserCompat.MediaItem.FLAG_BROWSABLE
+                  | MediaBrowserCompat.MediaItem.FLAG_PLAYABLE);
+    }
     rootHints.putBoolean(BrowserRoot.EXTRA_RECENT, params.isRecent);
     rootHints.putBoolean(BrowserRoot.EXTRA_OFFLINE, params.isOffline);
     rootHints.putBoolean(BrowserRoot.EXTRA_SUGGESTED, params.isSuggested);

libraries/test_session_common/src/main/java/androidx/media3/test/session/common/MediaBrowserConstants.java

@@ -25,6 +25,8 @@ import java.util.List;
 public class MediaBrowserConstants {
 
   public static final String ROOT_ID = "rootId";
+  public static final String ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY =
+      "root_id_supports_browsable_children_only";
   public static final Bundle ROOT_EXTRAS = new Bundle();
   public static final String ROOT_EXTRAS_KEY = "root_extras_key";
   public static final int ROOT_EXTRAS_VALUE = 4321;

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaBrowserCompatWithMediaLibraryServiceTest.java

@@ -45,6 +45,7 @@ import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_EXT
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_EXTRAS_KEY;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_EXTRAS_VALUE;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID;
+import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY;
 import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_QUERY;
 import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_QUERY_EMPTY_RESULT;
 import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_QUERY_ERROR;
@@ -615,4 +616,31 @@ public class MediaBrowserCompatWithMediaLibraryServiceTest
 
     assertThat(isSearchSupported).isFalse();
   }
+
+  @Test
+  public void rootBrowserHints_legacyBrowsableFlagSet_receivesRootWithBrowsableChildrenOnly()
+      throws Exception {
+    Bundle rootHints = new Bundle();
+    rootHints.putInt(
+        androidx.media.utils.MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS,
+        MediaItem.FLAG_BROWSABLE);
+    connectAndWait(rootHints);
+
+    String root = browserCompat.getRoot();
+
+    assertThat(root).isEqualTo(ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY);
+  }
+
+  @Test
+  public void rootBrowserHints_legacyPlayableFlagSet_receivesDefaultRoot() throws Exception {
+    Bundle connectionHints = new Bundle();
+    connectionHints.putInt(
+        androidx.media.utils.MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS,
+        MediaItem.FLAG_BROWSABLE | MediaItem.FLAG_PLAYABLE);
+    connectAndWait(connectionHints);
+
+    String root = browserCompat.getRoot();
+
+    assertThat(root).isEqualTo(ROOT_ID);
+  }
 }

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaBrowserCompatWithMediaSessionServiceTest.java

@@ -82,13 +82,12 @@ public class MediaBrowserCompatWithMediaSessionServiceTest {
     return MOCK_MEDIA3_SESSION_SERVICE;
   }
 
-  void connectAndWait(Bundle connectionHints) throws Exception {
+  void connectAndWait(Bundle rootHints) throws Exception {
     handler.postAndSync(
         () -> {
           // Make browser's internal handler to be initialized with test thread.
           browserCompat =
-              new MediaBrowserCompat(
+              new MediaBrowserCompat(context, getServiceComponent(), connectionCallback, rootHints);
-                  context, getServiceComponent(), connectionCallback, connectionHints);
         });
     browserCompat.connect();
     assertThat(connectionCallback.connectedLatch.await(SERVICE_CONNECTION_TIMEOUT_MS, MILLISECONDS))

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaBrowserListenerWithMediaBrowserServiceCompatTest.java

@@ -18,10 +18,13 @@ package androidx.media3.session;
 import static androidx.media3.session.LibraryResult.RESULT_SUCCESS;
 import static androidx.media3.session.MediaConstants.EXTRAS_KEY_COMPLETION_STATUS;
 import static androidx.media3.session.MediaConstants.EXTRAS_VALUE_COMPLETION_STATUS_PARTIALLY_PLAYED;
+import static androidx.media3.session.MediaConstants.EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY;
 import static androidx.media3.test.session.common.CommonConstants.MOCK_MEDIA_BROWSER_SERVICE_COMPAT;
 import static androidx.media3.test.session.common.MediaBrowserConstants.PARENT_ID;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_EXTRAS_KEY;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_EXTRAS_VALUE;
+import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID;
+import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY;
 import static androidx.media3.test.session.common.MediaBrowserServiceCompatConstants.TEST_CONNECT_REJECTED;
 import static androidx.media3.test.session.common.MediaBrowserServiceCompatConstants.TEST_GET_CHILDREN;
 import static androidx.media3.test.session.common.MediaBrowserServiceCompatConstants.TEST_GET_LIBRARY_ROOT;
@@ -163,6 +166,48 @@ public class MediaBrowserListenerWithMediaBrowserServiceCompatTest {
     assertThat(extras.getInt(ROOT_EXTRAS_KEY, ROOT_EXTRAS_VALUE + 1)).isEqualTo(ROOT_EXTRAS_VALUE);
   }
 
+  @Test
+  public void getLibraryRoot_browsableRootChildrenOnly_receivesRootWithBrowsableChildrenOnly()
+      throws Exception {
+    remoteService.setProxyForTest(TEST_GET_LIBRARY_ROOT);
+    MediaBrowser browser = createBrowser(/* listener= */ null);
+
+    LibraryResult<MediaItem> resultForLibraryRoot =
+        threadTestRule
+            .getHandler()
+            .postAndSync(
+                () -> {
+                  Bundle extras = new Bundle();
+                  extras.putBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY, true);
+                  return browser.getLibraryRoot(
+                      new LibraryParams.Builder().setExtras(extras).build());
+                })
+            .get(TIMEOUT_MS, MILLISECONDS);
+
+    assertThat(resultForLibraryRoot.value.mediaId)
+        .isEqualTo(ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY);
+  }
+
+  @Test
+  public void getLibraryRoot_browsableRootChildrenOnlyFalse_receivesDefaultRoot() throws Exception {
+    remoteService.setProxyForTest(TEST_GET_LIBRARY_ROOT);
+    MediaBrowser browser = createBrowser(/* listener= */ null);
+
+    LibraryResult<MediaItem> resultForLibraryRoot =
+        threadTestRule
+            .getHandler()
+            .postAndSync(
+                () -> {
+                  Bundle extras = new Bundle();
+                  extras.putBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY, false);
+                  return browser.getLibraryRoot(
+                      new LibraryParams.Builder().setExtras(extras).build());
+                })
+            .get(TIMEOUT_MS, MILLISECONDS);
+
+    assertThat(resultForLibraryRoot.value.mediaId).isEqualTo(ROOT_ID);
+  }
+
   @Test
   public void getChildren_correctMetadataExtras() throws Exception {
     LibraryParams params = MediaTestUtils.createLibraryParams();

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaUtilsTest.java

@@ -15,8 +15,12 @@
  */
 package androidx.media3.session;
 
+import static android.support.v4.media.MediaBrowserCompat.MediaItem.FLAG_BROWSABLE;
+import static android.support.v4.media.MediaBrowserCompat.MediaItem.FLAG_PLAYABLE;
 import static android.support.v4.media.MediaMetadataCompat.METADATA_KEY_DURATION;
 import static android.support.v4.media.session.MediaSessionCompat.FLAG_HANDLES_QUEUE_COMMANDS;
+import static androidx.media.utils.MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS;
+import static androidx.media3.session.MediaConstants.EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY;
 import static com.google.common.truth.Truth.assertThat;
 import static java.util.concurrent.TimeUnit.SECONDS;
 
@@ -34,6 +38,7 @@ import android.support.v4.media.session.MediaSessionCompat;
 import android.support.v4.media.session.PlaybackStateCompat;
 import androidx.annotation.Nullable;
 import androidx.media.AudioAttributesCompat;
+import androidx.media.utils.MediaConstants;
 import androidx.media3.common.AudioAttributes;
 import androidx.media3.common.C;
 import androidx.media3.common.HeartRating;
@@ -271,16 +276,54 @@ public final class MediaUtilsTest {
     assertThat(MediaUtils.convertToLibraryParams(context, null)).isNull();
     Bundle rootHints = new Bundle();
     rootHints.putString("key", "value");
+    rootHints.putInt(
+        MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS, FLAG_BROWSABLE);
     rootHints.putBoolean(MediaBrowserService.BrowserRoot.EXTRA_OFFLINE, true);
     rootHints.putBoolean(MediaBrowserService.BrowserRoot.EXTRA_RECENT, true);
     rootHints.putBoolean(MediaBrowserService.BrowserRoot.EXTRA_SUGGESTED, true);
 
     MediaLibraryService.LibraryParams params =
         MediaUtils.convertToLibraryParams(context, rootHints);
+
+    assertThat(params.extras.getString("key")).isEqualTo("value");
+    assertThat(params.extras.getBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY)).isTrue();
+    assertThat(params.extras.containsKey(BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS))
+        .isFalse();
     assertThat(params.isOffline).isTrue();
     assertThat(params.isRecent).isTrue();
     assertThat(params.isSuggested).isTrue();
-    assertThat(params.extras.getString("key")).isEqualTo("value");
+  }
+
+  @Test
+  public void convertToLibraryParams_rootHintsBrowsableNoFlagSet_browsableOnlyFalse() {
+    Bundle rootHints = new Bundle();
+    rootHints.putInt(MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS, 0);
+
+    MediaLibraryService.LibraryParams params =
+        MediaUtils.convertToLibraryParams(context, rootHints);
+
+    assertThat(params.extras.getBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY)).isFalse();
+  }
+
+  @Test
+  public void convertToLibraryParams_rootHintsPlayableFlagSet_browsableOnlyFalse() {
+    Bundle rootHints = new Bundle();
+    rootHints.putInt(
+        MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS,
+        FLAG_PLAYABLE | FLAG_BROWSABLE);
+
+    MediaLibraryService.LibraryParams params =
+        MediaUtils.convertToLibraryParams(context, rootHints);
+
+    assertThat(params.extras.getBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY)).isFalse();
+  }
+
+  @Test
+  public void convertToLibraryParams_rootHintsBrowsableAbsentKey_browsableOnlyFalse() {
+    MediaLibraryService.LibraryParams params =
+        MediaUtils.convertToLibraryParams(context, /* legacyBundle= */ Bundle.EMPTY);
+
+    assertThat(params.extras.getBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY)).isFalse();
   }
 
   @Test
@@ -288,6 +331,7 @@ public final class MediaUtilsTest {
     assertThat(MediaUtils.convertToRootHints(null)).isNull();
     Bundle extras = new Bundle();
     extras.putString("key", "value");
+    extras.putBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY, true);
     MediaLibraryService.LibraryParams param =
         new MediaLibraryService.LibraryParams.Builder()
             .setOffline(true)
@@ -295,11 +339,44 @@ public final class MediaUtilsTest {
             .setSuggested(true)
             .setExtras(extras)
             .build();
+
     Bundle rootHints = MediaUtils.convertToRootHints(param);
+
+    assertThat(
+            rootHints.getInt(
+                BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS, /* defaultValue= */ 0))
+        .isEqualTo(FLAG_BROWSABLE);
+    assertThat(rootHints.getString("key")).isEqualTo("value");
+    assertThat(rootHints.get(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY)).isNull();
     assertThat(rootHints.getBoolean(MediaBrowserService.BrowserRoot.EXTRA_OFFLINE)).isTrue();
     assertThat(rootHints.getBoolean(MediaBrowserService.BrowserRoot.EXTRA_RECENT)).isTrue();
     assertThat(rootHints.getBoolean(MediaBrowserService.BrowserRoot.EXTRA_SUGGESTED)).isTrue();
-    assertThat(rootHints.getString("key")).isEqualTo("value");
+  }
+
+  @Test
+  public void convertToRootHints_browsableOnlyFalse_correctLegacyBrowsableFlags() {
+    Bundle extras = new Bundle();
+    extras.putBoolean(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY, false);
+    MediaLibraryService.LibraryParams param =
+        new MediaLibraryService.LibraryParams.Builder().setExtras(extras).build();
+
+    Bundle rootHints = MediaUtils.convertToRootHints(param);
+
+    assertThat(
+            rootHints.getInt(
+                BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS, /* defaultValue= */ -1))
+        .isEqualTo(FLAG_BROWSABLE | FLAG_PLAYABLE);
+    assertThat(rootHints.get(EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY)).isNull();
+  }
+
+  @Test
+  public void convertToRootHints_browsableAbsentKey_noLegacyKeyAdded() {
+    MediaLibraryService.LibraryParams param =
+        new MediaLibraryService.LibraryParams.Builder().build();
+
+    Bundle rootHints = MediaUtils.convertToRootHints(param);
+
+    assertThat(rootHints.get(BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS)).isNull();
   }
 
   @Test

libraries/test_session_current/src/main/java/androidx/media3/session/MockMediaBrowserServiceCompat.java

@@ -22,6 +22,7 @@ import static androidx.media3.session.MediaConstants.EXTRAS_VALUE_COMPLETION_STA
 import static androidx.media3.test.session.common.CommonConstants.SUPPORT_APP_PACKAGE_NAME;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_EXTRAS;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID;
+import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY;
 import static androidx.media3.test.session.common.MediaBrowserServiceCompatConstants.TEST_CONNECT_REJECTED;
 import static androidx.media3.test.session.common.MediaBrowserServiceCompatConstants.TEST_GET_CHILDREN;
 import static androidx.media3.test.session.common.MediaBrowserServiceCompatConstants.TEST_GET_LIBRARY_ROOT;
@@ -37,6 +38,7 @@ import android.support.v4.media.MediaDescriptionCompat;
 import android.support.v4.media.session.MediaSessionCompat;
 import android.support.v4.media.session.MediaSessionCompat.Callback;
 import androidx.annotation.GuardedBy;
+import androidx.annotation.Nullable;
 import androidx.media.MediaBrowserServiceCompat;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.test.session.common.IRemoteMediaBrowserServiceCompat;
@@ -303,7 +305,18 @@ public class MockMediaBrowserServiceCompat extends MediaBrowserServiceCompat {
           new MockMediaBrowserServiceCompat.Proxy() {
             @Override
             public BrowserRoot onGetRoot(
-                String clientPackageName, int clientUid, Bundle rootHints) {
+                String clientPackageName, int clientUid, @Nullable Bundle rootHints) {
+              if (rootHints != null) {
+                // On API levels lower than 21 root hints are null.
+                int supportedRootChildrenFlags =
+                    rootHints.getInt(
+                        androidx.media.utils.MediaConstants
+                            .BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_SUPPORTED_FLAGS,
+                        /* defaultValue= */ 0);
+                if ((supportedRootChildrenFlags == MediaItem.FLAG_BROWSABLE)) {
+                  return new BrowserRoot(ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY, ROOT_EXTRAS);
+                }
+              }
               return new BrowserRoot(ROOT_ID, ROOT_EXTRAS);
             }
           });

libraries/test_session_current/src/main/java/androidx/media3/session/MockMediaLibraryService.java

@@ -20,6 +20,7 @@ import static androidx.media3.session.MediaConstants.EXTRAS_KEY_COMPLETION_STATU
 import static androidx.media3.session.MediaConstants.EXTRAS_KEY_ERROR_RESOLUTION_ACTION_INTENT_COMPAT;
 import static androidx.media3.session.MediaConstants.EXTRAS_KEY_ERROR_RESOLUTION_ACTION_LABEL_COMPAT;
 import static androidx.media3.session.MediaConstants.EXTRAS_VALUE_COMPLETION_STATUS_PARTIALLY_PLAYED;
+import static androidx.media3.session.MediaConstants.EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY;
 import static androidx.media3.session.MediaTestUtils.assertLibraryParamsEquals;
 import static androidx.media3.test.session.common.CommonConstants.SUPPORT_APP_PACKAGE_NAME;
 import static androidx.media3.test.session.common.MediaBrowserConstants.CUSTOM_ACTION;
@@ -39,6 +40,7 @@ import static androidx.media3.test.session.common.MediaBrowserConstants.PARENT_I
 import static androidx.media3.test.session.common.MediaBrowserConstants.PARENT_ID_LONG_LIST;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_EXTRAS;
 import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID;
+import static androidx.media3.test.session.common.MediaBrowserConstants.ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY;
 import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_QUERY;
 import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_QUERY_EMPTY_RESULT;
 import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_QUERY_LONG_LIST;
@@ -232,6 +234,22 @@ public class MockMediaLibraryService extends MediaLibraryService {
                         .build())
                 .build();
       }
+      if (params != null) {
+        boolean browsableRootChildrenOnly =
+            params.extras.getBoolean(
+                EXTRA_KEY_ROOT_CHILDREN_BROWSABLE_ONLY, /* defaultValue= */ false);
+        if (browsableRootChildrenOnly) {
+          rootItem =
+              new MediaItem.Builder()
+                  .setMediaId(ROOT_ID_SUPPORTS_BROWSABLE_CHILDREN_ONLY)
+                  .setMediaMetadata(
+                      new MediaMetadata.Builder()
+                          .setFolderType(MediaMetadata.FOLDER_TYPE_MIXED)
+                          .setIsPlayable(false)
+                          .build())
+                  .build();
+        }
+      }
       return Futures.immediateFuture(LibraryResult.ofItem(rootItem, ROOT_PARAMS));
     }