Notify consistent event information to listeners

Issue: #4262

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=197126757

RELEASENOTES.md

@@ -11,6 +11,9 @@
     ([#2843](https://github.com/google/ExoPlayer/issues/2843)).
 * Fix crash when switching surface on Moto E(4)
   ([#4134](https://github.com/google/ExoPlayer/issues/4134)).
+* Fix a bug that could cause event listeners to be called with inconsistent
+  information if an event listener interacted with the player
+  ([#4262](https://github.com/google/ExoPlayer/issues/4262)).
 * Audio:
   * Fix extraction of PCM in MP4/MOV
     ([#4228](https://github.com/google/ExoPlayer/issues/4228)).

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

@@ -185,10 +185,6 @@ public interface ExoPlayer extends Player {
    */
   Looper getPlaybackLooper();
 
-  @Override
-  @Nullable
-  ExoPlaybackException getPlaybackError();
-
   /**
    * Prepares the player to play the provided {@link MediaSource}. Equivalent to
    * {@code prepare(mediaSource, true, true)}.

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

@@ -193,6 +193,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
     if (this.playWhenReady != playWhenReady) {
       this.playWhenReady = playWhenReady;
       internalPlayer.setPlayWhenReady(playWhenReady);
+      PlaybackInfo playbackInfo = this.playbackInfo;
       for (Player.EventListener listener : listeners) {
         listener.onPlayerStateChanged(playWhenReady, playbackInfo.playbackState);
       }
@@ -570,7 +571,8 @@ import java.util.concurrent.CopyOnWriteArraySet;
         }
         break;
       case ExoPlayerImplInternal.MSG_ERROR:
-        playbackError = (ExoPlaybackException) msg.obj;
+        ExoPlaybackException playbackError = (ExoPlaybackException) msg.obj;
+        this.playbackError = playbackError;
         for (Player.EventListener listener : listeners) {
           listener.onPlayerError(playbackError);
         }
@@ -652,7 +654,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
     boolean playbackStateChanged = playbackInfo.playbackState != newPlaybackInfo.playbackState;
     boolean isLoadingChanged = playbackInfo.isLoading != newPlaybackInfo.isLoading;
     boolean trackSelectorResultChanged =
-        this.playbackInfo.trackSelectorResult != newPlaybackInfo.trackSelectorResult;
+        playbackInfo.trackSelectorResult != newPlaybackInfo.trackSelectorResult;
     playbackInfo = newPlaybackInfo;
     if (timelineOrManifestChanged || timelineChangeReason == TIMELINE_CHANGE_REASON_PREPARED) {
       for (Player.EventListener listener : listeners) {