Update ExoPlayerImplInternal with shuffle mode changes.

The shuffle mode is saved using a message on the playback thread.
After setting the shuffle mode, the same media period holder verification
as for repeat mode changes gets executed.

Note: the shuffle mode is not used yet to change the playback order.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=166060231

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

@@ -107,7 +107,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
     };
     playbackInfo = new ExoPlayerImplInternal.PlaybackInfo(0, 0);
     internalPlayer = new ExoPlayerImplInternal(renderers, trackSelector, loadControl, playWhenReady,
-        repeatMode, eventHandler, playbackInfo, this);
+        repeatMode, shuffleModeEnabled, eventHandler, playbackInfo, this);
   }
 
   @Override
@@ -195,6 +195,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
   public void setShuffleModeEnabled(boolean shuffleModeEnabled) {
     if (this.shuffleModeEnabled != shuffleModeEnabled) {
       this.shuffleModeEnabled = shuffleModeEnabled;
+      internalPlayer.setShuffleModeEnabled(shuffleModeEnabled);
       for (Player.EventListener listener : listeners) {
         listener.onShuffleModeEnabledChanged(shuffleModeEnabled);
       }
@@ -530,4 +531,3 @@ import java.util.concurrent.CopyOnWriteArraySet;
   }
 
 }
-

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

@@ -128,6 +128,7 @@ import java.io.IOException;
   private static final int MSG_TRACK_SELECTION_INVALIDATED = 10;
   private static final int MSG_CUSTOM = 11;
   private static final int MSG_SET_REPEAT_MODE = 12;
+  private static final int MSG_SET_SHUFFLE_ENABLED = 13;
 
   private static final int PREPARING_SOURCE_INTERVAL_MS = 10;
   private static final int RENDERING_INTERVAL_MS = 10;
@@ -173,6 +174,7 @@ import java.io.IOException;
   private boolean isLoading;
   private int state;
   private @Player.RepeatMode int repeatMode;
+  private boolean shuffleModeEnabled;
   private int customMessagesSent;
   private int customMessagesProcessed;
   private long elapsedRealtimeUs;
@@ -189,12 +191,14 @@ import java.io.IOException;
 
   public ExoPlayerImplInternal(Renderer[] renderers, TrackSelector trackSelector,
       LoadControl loadControl, boolean playWhenReady, @Player.RepeatMode int repeatMode,
-      Handler eventHandler, PlaybackInfo playbackInfo, ExoPlayer player) {
+      boolean shuffleModeEnabled, Handler eventHandler, PlaybackInfo playbackInfo,
+      ExoPlayer player) {
     this.renderers = renderers;
     this.trackSelector = trackSelector;
     this.loadControl = loadControl;
     this.playWhenReady = playWhenReady;
     this.repeatMode = repeatMode;
+    this.shuffleModeEnabled = shuffleModeEnabled;
     this.eventHandler = eventHandler;
     this.state = Player.STATE_IDLE;
     this.playbackInfo = playbackInfo;
@@ -234,6 +238,10 @@ import java.io.IOException;
     handler.obtainMessage(MSG_SET_REPEAT_MODE, repeatMode, 0).sendToTarget();
   }
 
+  public void setShuffleModeEnabled(boolean shuffleModeEnabled) {
+    handler.obtainMessage(MSG_SET_SHUFFLE_ENABLED, shuffleModeEnabled ? 1 : 0, 0).sendToTarget();
+  }
+
   public void seekTo(Timeline timeline, int windowIndex, long positionUs) {
     handler.obtainMessage(MSG_SEEK_TO, new SeekPosition(timeline, windowIndex, positionUs))
         .sendToTarget();
@@ -346,6 +354,10 @@ import java.io.IOException;
           setRepeatModeInternal(msg.arg1);
           return true;
         }
+        case MSG_SET_SHUFFLE_ENABLED: {
+          setShuffleModeEnabledInternal(msg.arg1 != 0);
+          return true;
+        }
         case MSG_DO_SOME_WORK: {
           doSomeWork();
           return true;
@@ -457,7 +469,17 @@ import java.io.IOException;
       throws ExoPlaybackException {
     this.repeatMode = repeatMode;
     mediaPeriodInfoSequence.setRepeatMode(repeatMode);
+    validateExistingPeriodHolders();
+  }
+
+  private void setShuffleModeEnabledInternal(boolean shuffleModeEnabled)
+      throws ExoPlaybackException {
+    this.shuffleModeEnabled = shuffleModeEnabled;
+    mediaPeriodInfoSequence.setShuffleModeEnabled(shuffleModeEnabled);
+    validateExistingPeriodHolders();
+  }
 
+  private void validateExistingPeriodHolders() throws ExoPlaybackException {
     // Find the last existing period holder that matches the new period order.
     MediaPeriodHolder lastValidPeriodHolder = playingPeriodHolder != null
         ? playingPeriodHolder : loadingPeriodHolder;

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

@@ -102,8 +102,8 @@ import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
   private final Timeline.Window window;
 
   private Timeline timeline;
-  @RepeatMode
-  private int repeatMode;
+  private @RepeatMode int repeatMode;
+  private boolean shuffleModeEnabled;
 
   /**
    * Creates a new media period info sequence.
@@ -130,6 +130,14 @@ import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
   }
 
   /**
+   * Sets whether shuffling is enabled. Call {@link #getUpdatedMediaPeriodInfo} to update period
+   * information taking into account the shuffle mode.
+   */
+  public void setShuffleModeEnabled(boolean shuffleModeEnabled) {
+    this.shuffleModeEnabled = shuffleModeEnabled;
+  }
+
+  /**
    * Returns the first {@link MediaPeriodInfo} to play, based on the specified playback position.
    */
   public MediaPeriodInfo getFirstMediaPeriodInfo(PlaybackInfo playbackInfo) {