Fix transfer from Cast to Local

This CL fixes a regression where, upon a transfer to "This phone", the
queue callback would send an empty queue event before onSessionEnded.
This means it's not possible to transfer the playback queue back to
local, since it's empty from the point of view of the RemoteCastPlayer
client.

To fix this, we assume the session is ended earlier, in onSessionEnding.
And we also prevent updating the timeline if the session is not active.
This prevents us from updating the timeline upon a queue event after
onSessionEnding.

PiperOrigin-RevId: 862208017
(cherry picked from commit 481a2be)

Author: AquilesCanta

libraries/cast/src/main/java/androidx/media3/cast/RemoteCastPlayer.java

@@ -1279,6 +1279,10 @@ private void updateRepeatModeAndNotifyIfChanged(@Nullable ResultCallback<?> resu
    */
   @SuppressWarnings("deprecation") // Calling deprecated listener method.
   private boolean updateTimelineAndNotifyIfChanged() {
+    if (remoteMediaClient == null) {
+      // There is no session. We leave the state of the player as it is now.
+      return false;
+    }
     Timeline oldTimeline = currentTimeline;
     int oldWindowIndex = currentWindowIndex;
     boolean playingPeriodChanged = false;
@@ -1858,7 +1862,12 @@ public void onSessionStartFailed(CastSession castSession, int statusCode) {
 
     @Override
     public void onSessionEnding(CastSession castSession) {
-      // Do nothing.
+      // We don't wait until the onSessionEnded event because the media queue callback will send
+      // updates before that (but after onSessionEnding) indicating the queue is being cleared. This
+      // complicates playback state transfer to local. As a result, we clear the active cast session
+      // here so that the player keeps reflecting the state at this point in time, before the queue
+      // is cleared. See [internal: b/479112029].
+      setCastSession(null);
     }
 
     @Override

libraries/cast/src/test/java/androidx/media3/cast/RemoteCastPlayerTest.java

@@ -89,6 +89,7 @@
 import com.google.android.gms.cast.framework.CastContext;
 import com.google.android.gms.cast.framework.CastSession;
 import com.google.android.gms.cast.framework.SessionManager;
+import com.google.android.gms.cast.framework.SessionManagerListener;
 import com.google.android.gms.cast.framework.media.MediaQueue;
 import com.google.android.gms.cast.framework.media.RemoteMediaClient;
 import com.google.android.gms.common.api.PendingResult;
@@ -115,6 +116,7 @@ public class RemoteCastPlayerTest {
   private RemoteCastPlayer remoteCastPlayer;
   private DefaultMediaItemConverter mediaItemConverter;
   private Cast.Listener castListener;
+  private SessionManagerListener<CastSession> sessionManagerListener;
   private RemoteMediaClient.Callback remoteMediaClientCallback;
   private MediaQueue.Callback mediaQueueCallback;
 
@@ -133,6 +135,8 @@ public class RemoteCastPlayerTest {
 
   @Captor private ArgumentCaptor<Cast.Listener> castListenerArgumentCaptor;
 
+  @Captor private ArgumentCaptor<SessionManagerListener<CastSession>> sessionManagerListenerCaptor;
+
   @Captor
   private ArgumentCaptor<RemoteMediaClient.Callback> remoteMediaClientCallbackArgumentCaptor;
 
@@ -167,6 +171,9 @@ public void setUp() {
             C.DEFAULT_SEEK_FORWARD_INCREMENT_MS,
             C.DEFAULT_MAX_SEEK_TO_PREVIOUS_POSITION_MS);
     remoteCastPlayer.addListener(mockListener);
+    verify(mockSessionManager)
+        .addSessionManagerListener(sessionManagerListenerCaptor.capture(), eq(CastSession.class));
+    sessionManagerListener = sessionManagerListenerCaptor.getValue();
     verify(mockCastSession).addCastListener(castListenerArgumentCaptor.capture());
     castListener = castListenerArgumentCaptor.getValue();
     verify(mockRemoteMediaClient)
@@ -2382,6 +2389,41 @@ private void updateTimeLine(
     }
   }
 
+  @Test
+  public void mediaQueueChanged_afterOnSessionEnding_doesNotClearTheTimeline() {
+    List<MediaItem> firstPlaylist = new ArrayList<>();
+    String uri1 = "http://www.google.com/video1";
+    String uri2 = "http://www.google.com/video2";
+    int firstItemId = 33;
+    firstPlaylist.add(
+        new MediaItem.Builder().setUri(uri1).setMimeType(MimeTypes.APPLICATION_MPD).build());
+    firstPlaylist.add(
+        new MediaItem.Builder().setUri(uri2).setMimeType(MimeTypes.APPLICATION_MP4).build());
+    remoteCastPlayer.setMediaItems(
+        firstPlaylist, /* startIndex= */ 1, /* startPositionMs= */ 2000L);
+    when(mockRemoteMediaClient.getPlayerState()).thenReturn(MediaStatus.PLAYER_STATE_BUFFERING);
+    updateTimeLine(
+        firstPlaylist, /* mediaQueueItemIds= */ new int[] {firstItemId, 2}, /* currentItemId= */ 1);
+    mediaQueueCallback.mediaQueueChanged();
+    clearInvocations(mockListener);
+    Timeline initialTimeline = remoteCastPlayer.getCurrentTimeline();
+
+    sessionManagerListener.onSessionEnding(mockCastSession);
+    updateTimeLine(
+        /* mediaItems= */ ImmutableList.of(),
+        /* mediaQueueItemIds= */ new int[] {},
+        /* currentItemId= */ C.INDEX_UNSET,
+        /* streamTypes= */ new int[] {},
+        /* durationsMs= */ new long[] {},
+        /* positionMs= */ 0,
+        /* notifyStatusUpdate= */ true);
+    mediaQueueCallback.mediaQueueChanged();
+
+    Timeline timelineAfterSessionEnd = remoteCastPlayer.getCurrentTimeline();
+    verify(mockListener, never()).onTimelineChanged(any(), anyInt());
+    assertThat(initialTimeline).isEqualTo(timelineAfterSessionEnd);
+  }
+
   private static Player.Commands createWithDefaultCommands(
       boolean isTimelineEmpty, @Player.Command int... additionalCommands) {
     Player.Commands.Builder builder = new Player.Commands.Builder();