Fix an issue that audio and video may run out of sync

media/base/android/java/src/org/chromium/media/MediaCodecBridge.java

Index: media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
diff --git a/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java b/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
index 3f1506113848f1cecd9dd045f6def102e8b2d946..f7f2b5223ddd39bdcbcfcfe380f49f533fbe8b33 100644
--- a/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
+++ b/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
@@ -280,6 +280,8 @@ class MediaCodecBridge {
         try {
             mFlushed = true;
             if (mAudioTrack != null) {
+                // Need to call pause() here, or otherwise flush() is a no-op.
+                mAudioTrack.pause();
                 mAudioTrack.flush();
             }
             mMediaCodec.flush();
@@ -520,8 +522,15 @@ class MediaCodecBridge {
         return false;
     }
 
+    /**
+     *  Play the audio buffer that is passed in.
+     *
+     *  @param buf Audio buffer to be rendered.
+     *  @return The number of frames that have already been consumed by the
+     *  hardware. This number resets to 0 after each flush call.
+     */
     @CalledByNative
-    private void playOutputBuffer(byte[] buf) {
+    private long playOutputBuffer(byte[] buf) {
         if (mAudioTrack != null) {
             if (AudioTrack.PLAYSTATE_PLAYING != mAudioTrack.getPlayState()) {
                 mAudioTrack.play();
@@ -531,7 +540,17 @@ class MediaCodecBridge {
                 Log.i(TAG, "Failed to send all data to audio output, expected size: " +
                         buf.length + ", actual size: " + size);
             }
+            // TODO(qinmin): Returning the head position allows us to estimate
+            // the current presentation time in native code. However, it is
+            // better to use AudioTrack.getCurrentTimestamp() to get the last
+            // known time when a frame is played. However, we will need to
+            // convert the java nano time to C++ timestamp.
+            // If the stream runs too long, getPlaybackHeadPosition() could
+            // overflow. AudioTimestampHelper in MediaSourcePlayer has the same
+            // issue. See http://crbug.com/358801.
+            return mAudioTrack.getPlaybackHeadPosition();
         }
+        return 0;
     }
 
     @CalledByNative