[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 935a8a9a45d16d8fc8c040cb5281af2372f41f40..b47f6b3402465d153274106d5997b5efaa9e8daf 100644
--- a/ppapi/proxy/media_stream_video_track_resource.h
+++ b/ppapi/proxy/media_stream_video_track_resource.h
@@ -45,10 +45,10 @@ 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();