[PPAPI] Pepper MediaStream API audio track implementation and example.

ppapi/proxy/media_stream_video_track_resource.h

Index: ppapi/proxy/media_stream_video_track_resource.h
diff --git a/ppapi/proxy/media_stream_video_track_resource.h b/ppapi/proxy/media_stream_video_track_resource.h
index e402b0c68effbe1ee260132ba661a28989442cd7..2935994303c58e16ff4edade7332a77c0f330f86 100644
--- a/ppapi/proxy/media_stream_video_track_resource.h
+++ b/ppapi/proxy/media_stream_video_track_resource.h
@@ -43,10 +43,10 @@ class PPAPI_PROXY_EXPORT MediaStreamVideoTrackResource
   virtual void Close() OVERRIDE;
 
   // MediaStreamFrameBuffer::Delegate overrides:
-  virtual void OnNewFrameEnqueued() OVERRIDE;
+  virtual bool OnNewFramePreEnqueued(int32_t index) OVERRIDE;
 
  private:
-  PP_Resource GetVideoFrame();
+  PP_Resource GetVideoFrame(int32_t index);
 
   void ReleaseFrames();