Simplify VideoDecodeEngine interface by making everything synchronous.

content/renderer/media/rtc_video_decoder.h

Index: content/renderer/media/rtc_video_decoder.h
diff --git a/content/renderer/media/rtc_video_decoder.h b/content/renderer/media/rtc_video_decoder.h
index eb59e2279ad950a901ccdcc3a897ccacd948f1d4..653527089952a58485c43f4c962fc41685ecc60b 100644
--- a/content/renderer/media/rtc_video_decoder.h
+++ b/content/renderer/media/rtc_video_decoder.h
@@ -43,8 +43,7 @@ class CONTENT_EXPORT RTCVideoDecoder
       media::DemuxerStream* demuxer_stream,
       const base::Closure& filter_callback,
       const media::StatisticsCallback& stat_callback) OVERRIDE;
-  virtual void ProduceVideoFrame(
-      scoped_refptr<media::VideoFrame> video_frame) OVERRIDE;
+  virtual void Read(const FrameReadyCB& callback) OVERRIDE;
   virtual gfx::Size natural_size() OVERRIDE;
 
   // cricket::VideoRenderer implementation
@@ -61,7 +60,6 @@ class CONTENT_EXPORT RTCVideoDecoder
   enum DecoderState {
     kUnInitialized,
     kNormal,
-    kSeeking,
     kPaused,
     kStopped
   };
@@ -70,8 +68,9 @@ class CONTENT_EXPORT RTCVideoDecoder
   gfx::Size visible_size_;
   std::string url_;
   DecoderState state_;
-  std::deque<scoped_refptr<media::VideoFrame> > frame_queue_available_;
-  // Used for accessing frame queue from another thread.
+  FrameReadyCB frame_ready_cb_;
+
+  // Used for accessing |state_| and |frame_ready_cb| from another thread.
   base::Lock lock_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCVideoDecoder);