Notify listeners of error changes when masking in MediaControllerImplBase

Currently, the implementation of `MediaControllerImplBase` differs from `ExoPlayerImpl`. The listeners of the former are notified of player error changes only in `onPlayerInfoChanged` and not `updatePlayerInfo` (masking method). Whereas `ExoPlayerImpl` has one unified method - `updatePlaybackInfo` - which sends the events to all the available listeners.

This change fixes the lack of 2 particular callbacks - `onPlayerErrorChanged` and `onPlayerError`, however, there might be more differences. Ideally, there should be a unified method for oldPlayerInfo/newPlayerInfo comparison-update-notify-listeners flow.

Issue: androidx/media#449

#minor-release

PiperOrigin-RevId: 539961618
(cherry picked from commit 4b5a4577905d86ec6e24a92a088a65689c7be901)

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

@@ -421,13 +421,13 @@ import org.checkerframework.checker.nullness.qual.NonNull;
         (iSession, seq) -> iSession.prepare(controllerStub, seq));
 
     if (playerInfo.playbackState == Player.STATE_IDLE) {
-      PlayerInfo playerInfo =
+      PlayerInfo newPlayerInfo =
           this.playerInfo.copyWithPlaybackState(
               this.playerInfo.timeline.isEmpty() ? Player.STATE_ENDED : Player.STATE_BUFFERING,
               /* playerError= */ null);
 
       updatePlayerInfo(
-          playerInfo,
+          newPlayerInfo,
           /* ignored */ Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED,
           /* ignored */ Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST,
           /* positionDiscontinuity= */ false,
@@ -2152,11 +2152,11 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     // Update position and then stop estimating until a new positionInfo arrives from the player.
     maybeUpdateCurrentPositionMs();
     lastSetPlayWhenReadyCalledTimeMs = SystemClock.elapsedRealtime();
-    PlayerInfo playerInfo =
+    PlayerInfo newPlayerInfo =
         this.playerInfo.copyWithPlayWhenReady(
             playWhenReady, playWhenReadyChangeReason, playbackSuppressionReason);
     updatePlayerInfo(
-        playerInfo,
+        newPlayerInfo,
         /* ignored */ Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED,
         playWhenReadyChangeReason,
         /* positionDiscontinuity= */ false,
@@ -2199,6 +2199,21 @@ import org.checkerframework.checker.nullness.qual.NonNull;
           /* eventFlag= */ Player.EVENT_TIMELINE_CHANGED,
           listener -> listener.onTimelineChanged(newPlayerInfo.timeline, timelineChangeReason));
     }
+    PlaybackException oldPlayerError = oldPlayerInfo.playerError;
+    PlaybackException newPlayerError = newPlayerInfo.playerError;
+    boolean errorsMatch =
+        oldPlayerError == newPlayerError
+            || (oldPlayerError != null && oldPlayerError.errorInfoEquals(newPlayerError));
+    if (!errorsMatch) {
+      listeners.queueEvent(
+          /* eventFlag= */ Player.EVENT_PLAYER_ERROR,
+          listener -> listener.onPlayerErrorChanged(newPlayerError));
+      if (newPlayerError != null) {
+        listeners.queueEvent(
+            /* eventFlag= */ Player.EVENT_PLAYER_ERROR,
+            listener -> listener.onPlayerError(newPlayerError));
+      }
+    }
     if (oldPlayerInfo.playbackState != newPlayerInfo.playbackState) {
       listeners.queueEvent(
           /* eventFlag= */ Player.EVENT_PLAYBACK_STATE_CHANGED,

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

@@ -630,9 +630,10 @@ public class MediaControllerStateMaskingTest {
     remoteSession.setPlayer(playerConfig);
 
     MediaController controller = controllerTestRule.createController(remoteSession.getToken());
-    CountDownLatch latch = new CountDownLatch(2);
+    CountDownLatch latch = new CountDownLatch(3);
     AtomicInteger playbackStateFromCallbackRef = new AtomicInteger();
     AtomicReference<Player.Events> onEventsRef = new AtomicReference<>();
+    AtomicReference<PlaybackException> playerErrorFromCallbackRef = new AtomicReference<>();
     Player.Listener listener =
         new Player.Listener() {
           @Override
@@ -646,25 +647,32 @@ public class MediaControllerStateMaskingTest {
             onEventsRef.set(events);
             latch.countDown();
           }
+
+          @Override
+          public void onPlayerErrorChanged(@Nullable PlaybackException error) {
+            playerErrorFromCallbackRef.set(error);
+            latch.countDown();
+          }
         };
     threadTestRule.getHandler().postAndSync(() -> controller.addListener(listener));
     AtomicInteger playbackStateFromGetterRef = new AtomicInteger();
-    AtomicReference<PlaybackException> playerErrorRef = new AtomicReference<>();
+    AtomicReference<PlaybackException> playerErrorFromGetterRef = new AtomicReference<>();
     threadTestRule
         .getHandler()
         .postAndSync(
             () -> {
               controller.prepare();
               playbackStateFromGetterRef.set(controller.getPlaybackState());
-              playerErrorRef.set(controller.getPlayerError());
+              playerErrorFromGetterRef.set(controller.getPlayerError());
             });
 
     assertThat(latch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
     assertThat(playbackStateFromCallbackRef.get()).isEqualTo(testPlaybackState);
-    assertThat(getEventsAsList(onEventsRef.get()))
-        .containsExactly(Player.EVENT_PLAYBACK_STATE_CHANGED);
     assertThat(playbackStateFromGetterRef.get()).isEqualTo(testPlaybackState);
-    assertThat(playerErrorRef.get()).isNull();
+    assertThat(playerErrorFromGetterRef.get()).isNull();
+    assertThat(playerErrorFromCallbackRef.get()).isNull();
+    assertThat(getEventsAsList(onEventsRef.get()))
+        .containsExactly(Player.EVENT_PLAYBACK_STATE_CHANGED, Player.EVENT_PLAYER_ERROR);
   }
 
   @Test