Add format change events to SimpleExoPlayer.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=124344637

demo/src/main/java/com/google/android/exoplayer/demo/EventLogger.java

@@ -15,7 +15,6 @@
  */
 package com.google.android.exoplayer.demo;
 
-import com.google.android.exoplayer.C;
 import com.google.android.exoplayer.DefaultTrackSelector;
 import com.google.android.exoplayer.DefaultTrackSelector.TrackInfo;
 import com.google.android.exoplayer.ExoPlaybackException;
@@ -140,12 +139,24 @@ public class EventLogger implements ExoPlayer.EventListener, SimpleExoPlayer.Deb
   }
 
   @Override
+  public void onAudioFormatChanged(Format format) {
+    Log.d(TAG, "audioFormatChanged [" + getSessionTimeString() + ", " + getFormatString(format)
+        + "]");
+  }
+
+  @Override
   public void onVideoDecoderInitialized(String decoderName, long elapsedRealtimeMs,
       long initializationDurationMs) {
     Log.d(TAG, "videoDecoderInitialized [" + getSessionTimeString() + ", " + decoderName + "]");
   }
 
   @Override
+  public void onVideoFormatChanged(Format format) {
+    Log.d(TAG, "videoFormatChanged [" + getSessionTimeString() + ", " + getFormatString(format)
+        + "]");
+  }
+
+  @Override
   public void onDroppedFrames(int count, long elapsed) {
     Log.d(TAG, "droppedFrames [" + getSessionTimeString() + ", " + count + "]");
   }
@@ -200,9 +211,7 @@ public class EventLogger implements ExoPlayer.EventListener, SimpleExoPlayer.Deb
   @Override
   public void onDownstreamFormatChanged(int sourceId, Format format, int trigger,
       long mediaTimeMs) {
-    if (sourceId == C.TRACK_TYPE_VIDEO) {
-      Log.d(TAG, "videoFormatChanged [" + getSessionTimeString() + ", " + format.id + "]");
-    }
+    // Do nothing.
   }
 
   // Internal methods
@@ -266,6 +275,9 @@ public class EventLogger implements ExoPlayer.EventListener, SimpleExoPlayer.Deb
   }
 
   private static String getFormatString(Format format) {
+    if (format == null) {
+      return "null";
+    }
     StringBuilder builder = new StringBuilder();
     builder.append("id=").append(format.id).append(", mimeType=").append(format.sampleMimeType);
     if (format.bitrate != Format.NO_VALUE) {

library/src/main/java/com/google/android/exoplayer/SimpleExoPlayer.java

@@ -63,8 +63,10 @@ public final class SimpleExoPlayer implements ExoPlayer {
   public interface DebugListener {
     void onAudioDecoderInitialized(String decoderName, long elapsedRealtimeMs,
         long initializationDurationMs);
+    void onAudioFormatChanged(Format format);
     void onVideoDecoderInitialized(String decoderName, long elapsedRealtimeMs,
         long initializationDurationMs);
+    void onVideoFormatChanged(Format format);
     void onDroppedFrames(int count, long elapsed);
     void onAudioTrackUnderrun(int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs);
   }
@@ -481,6 +483,9 @@ public final class SimpleExoPlayer implements ExoPlayer {
     @Override
     public void onVideoInputFormatChanged(Format format) {
       videoFormat = format;
+      if (debugListener != null) {
+        debugListener.onVideoFormatChanged(format);
+      }
     }
 
     @Override
@@ -508,8 +513,13 @@ public final class SimpleExoPlayer implements ExoPlayer {
 
     @Override
     public void onVideoDisabled() {
-      videoFormat = null;
       videoCodecCounters = null;
+      if (videoFormat != null) {
+        videoFormat = null;
+        if (debugListener != null) {
+          debugListener.onVideoFormatChanged(null);
+        }
+      }
     }
 
     // AudioTrackRendererEventListener implementation
@@ -531,6 +541,9 @@ public final class SimpleExoPlayer implements ExoPlayer {
     @Override
     public void onAudioInputFormatChanged(Format format) {
       audioFormat = format;
+      if (debugListener != null) {
+        debugListener.onAudioFormatChanged(format);
+      }
     }
 
     @Override
@@ -543,8 +556,13 @@ public final class SimpleExoPlayer implements ExoPlayer {
 
     @Override
     public void onAudioDisabled() {
-      audioFormat = null;
       audioCodecCounters = null;
+      if (audioFormat != null) {
+        audioFormat = null;
+        if (debugListener != null) {
+          debugListener.onAudioFormatChanged(null);
+        }
+      }
     }
 
     // TextRenderer implementation