Fix onTimelineChanged call (timeline should never be null).

Issue: #2186

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=141790023

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

@@ -120,8 +120,8 @@ public interface ExoPlayer {
      * removed from the timeline. The will <em>not</em> be reported via a separate call to
      * removed from the timeline. The will <em>not</em> be reported via a separate call to
      * {@link #onPositionDiscontinuity()}.
      * {@link #onPositionDiscontinuity()}.
      *
      *
-     * @param timeline The latest timeline, or null if the timeline is being cleared.
-     * @param manifest The latest manifest, or null if the manifest is being cleared.
+     * @param timeline The latest timeline. Never null, but may be empty.
+     * @param manifest The latest manifest. May be null.
      */
      */
     void onTimelineChanged(Timeline timeline, Object manifest);
     void onTimelineChanged(Timeline timeline, Object manifest);
 
 

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

@@ -125,7 +125,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
         timeline = Timeline.EMPTY;
         timeline = Timeline.EMPTY;
         manifest = null;
         manifest = null;
         for (EventListener listener : listeners) {
         for (EventListener listener : listeners) {
-          listener.onTimelineChanged(null, null);
+          listener.onTimelineChanged(timeline, manifest);
         }
         }
       }
       }
       if (tracksSelected) {
       if (tracksSelected) {