Make MediaSessionConnector use getPlaybackError

It's no longer necessary to stash a reference to the
error yourself. This also correctly handles the case
where setPlayer is called with a player that's already
in an error state.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=194828387

extensions/cast/src/main/java/com/google/android/exoplayer2/ext/cast/CastPlayer.java

@@ -19,6 +19,7 @@ import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.util.Log;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.PlaybackParameters;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.Timeline;
@@ -308,7 +309,7 @@ public final class CastPlayer implements Player {
   }
 
   @Override
-  public Exception getPlaybackError() {
+  public ExoPlaybackException getPlaybackError() {
     return null;
   }
 

extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/MediaSessionConnector.java

@@ -339,7 +339,6 @@ public final class MediaSessionConnector {
   private QueueNavigator queueNavigator;
   private QueueEditor queueEditor;
   private RatingCallback ratingCallback;
-  private ExoPlaybackException playbackException;
 
   /**
    * Creates an instance. Must be called on the same thread that is used to construct the player
@@ -443,7 +442,10 @@ public final class MediaSessionConnector {
    */
   public void setErrorMessageProvider(
       ErrorMessageProvider<? super ExoPlaybackException> errorMessageProvider) {
-    this.errorMessageProvider = errorMessageProvider;
+    if (this.errorMessageProvider != errorMessageProvider) {
+      this.errorMessageProvider = errorMessageProvider;
+      updateMediaSessionPlaybackState();
+    }
   }
 
   /**
@@ -453,9 +455,11 @@ public final class MediaSessionConnector {
    * @param queueNavigator The queue navigator.
    */
   public void setQueueNavigator(QueueNavigator queueNavigator) {
-    unregisterCommandReceiver(this.queueNavigator);
-    this.queueNavigator = queueNavigator;
-    registerCommandReceiver(queueNavigator);
+    if (this.queueNavigator != queueNavigator) {
+      unregisterCommandReceiver(this.queueNavigator);
+      this.queueNavigator = queueNavigator;
+      registerCommandReceiver(queueNavigator);
+    }
   }
 
   /**
@@ -464,11 +468,13 @@ public final class MediaSessionConnector {
    * @param queueEditor The queue editor.
    */
   public void setQueueEditor(QueueEditor queueEditor) {
-    unregisterCommandReceiver(this.queueEditor);
-    this.queueEditor = queueEditor;
-    registerCommandReceiver(queueEditor);
-    mediaSession.setFlags(queueEditor == null ? BASE_MEDIA_SESSION_FLAGS
-        : EDITOR_MEDIA_SESSION_FLAGS);
+    if (this.queueEditor != queueEditor) {
+      unregisterCommandReceiver(this.queueEditor);
+      this.queueEditor = queueEditor;
+      registerCommandReceiver(queueEditor);
+      mediaSession.setFlags(
+          queueEditor == null ? BASE_MEDIA_SESSION_FLAGS : EDITOR_MEDIA_SESSION_FLAGS);
+    }
   }
 
   /**
@@ -477,9 +483,11 @@ public final class MediaSessionConnector {
    * @param ratingCallback The rating callback.
    */
   public void setRatingCallback(RatingCallback ratingCallback) {
-    unregisterCommandReceiver(this.ratingCallback);
-    this.ratingCallback = ratingCallback;
-    registerCommandReceiver(this.ratingCallback);
+    if (this.ratingCallback != ratingCallback) {
+      unregisterCommandReceiver(this.ratingCallback);
+      this.ratingCallback = ratingCallback;
+      registerCommandReceiver(this.ratingCallback);
+    }
   }
 
   private void registerCommandReceiver(CommandReceiver commandReceiver) {
@@ -516,16 +524,16 @@ public final class MediaSessionConnector {
     }
     customActionMap = Collections.unmodifiableMap(currentActions);
 
-    int sessionPlaybackState = playbackException != null ? PlaybackStateCompat.STATE_ERROR
-        : mapPlaybackState(player.getPlaybackState(), player.getPlayWhenReady());
-    if (playbackException != null) {
-      if (errorMessageProvider != null) {
-        Pair<Integer, String> message = errorMessageProvider.getErrorMessage(playbackException);
-        builder.setErrorMessage(message.first, message.second);
-      }
-      if (player.getPlaybackState() != Player.STATE_IDLE) {
-        playbackException = null;
-      }
+    int playbackState = player.getPlaybackState();
+    ExoPlaybackException playbackError =
+        playbackState == Player.STATE_IDLE ? player.getPlaybackError() : null;
+    int sessionPlaybackState =
+        playbackError != null
+            ? PlaybackStateCompat.STATE_ERROR
+            : mapPlaybackState(player.getPlaybackState(), player.getPlayWhenReady());
+    if (playbackError != null && errorMessageProvider != null) {
+      Pair<Integer, String> message = errorMessageProvider.getErrorMessage(playbackError);
+      builder.setErrorMessage(message.first, message.second);
     }
     long activeQueueItemId = queueNavigator != null ? queueNavigator.getActiveQueueItemId(player)
         : MediaSessionCompat.QueueItem.UNKNOWN_ID;
@@ -702,12 +710,6 @@ public final class MediaSessionConnector {
     }
 
     @Override
-    public void onPlayerError(ExoPlaybackException error) {
-      playbackException = error;
-      updateMediaSessionPlaybackState();
-    }
-
-    @Override
     public void onPositionDiscontinuity(@Player.DiscontinuityReason int reason) {
       if (currentWindowIndex != player.getCurrentWindowIndex()) {
         if (queueNavigator != null) {

library/core/src/main/java/com/google/android/exoplayer2/Player.java

@@ -468,7 +468,7 @@ public interface Player {
    * @return The error, or {@code null}.
    */
   @Nullable
-  Exception getPlaybackError();
+  ExoPlaybackException getPlaybackError();
 
   /**
    * Sets whether playback should proceed when {@link #getPlaybackState()} == {@link #STATE_READY}.