Pass in media message loop to VideoRendererBase and enforce calling on the right thread.

media/filters/video_renderer_base.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_FILTERS_VIDEO_RENDERER_BASE_H_
 #define MEDIA_FILTERS_VIDEO_RENDERER_BASE_H_
 
 #include <deque>
 
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/platform_thread.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/pipeline_status.h"
 #include "media/base/video_decoder.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_renderer.h"
 
+namespace base {
+class MessageLoopProxy;
+}
+
 namespace media {
 
 // VideoRendererBase creates its own thread for the sole purpose of timing frame
 // presentation.  It handles reading from the decoder and stores the results in
 // a queue of decoded frames and executing a callback when a frame is ready for
 // rendering.
 class MEDIA_EXPORT VideoRendererBase
     : public VideoRenderer,
       public base::PlatformThread::Delegate {
  public:
   typedef base::Callback<void(bool)> SetOpaqueCB;
 
   // Maximum duration of the last frame.
   static base::TimeDelta kMaxLastFrameDuration();
 
   // |paint_cb| is executed on the video frame timing thread whenever a new
   // frame is available for painting via GetCurrentFrame().
   //
   // |set_opaque_cb| is executed when the renderer is initialized to inform
   // the player whether the decoder's output will be opaque or not.
   //
   // Implementors should avoid doing any sort of heavy work in this method and
   // instead post a task to a common/worker thread to handle rendering.  Slowing
   // down the video thread may result in losing synchronization with audio.
   //
   // Setting |drop_frames_| to true causes the renderer to drop expired frames.
   //
   // TODO(scherkus): pass the VideoFrame* to this callback and remove
   // Get/PutCurrentFrame() http://crbug.com/108435
-  VideoRendererBase(const base::Closure& paint_cb,
+  VideoRendererBase(const scoped_refptr<base::MessageLoopProxy>& message_loop,
+                    const base::Closure& paint_cb,
                     const SetOpaqueCB& set_opaque_cb,
                     bool drop_frames);
 
   // VideoRenderer implementation.
   virtual void Initialize(const scoped_refptr<DemuxerStream>& stream,
                           const VideoDecoderList& decoders,
                           const PipelineStatusCB& init_cb,
                           const StatisticsCB& statistics_cb,
                           const TimeCB& max_time_cb,
                           const NaturalSizeChangedCB& size_changed_cb,
@@ skipping 28 matching lines @@
   // Callback from the video decoder delivering decoded video frames and
   // reporting video decoder status.
   void FrameReady(VideoDecoder::Status status,
                   const scoped_refptr<VideoFrame>& frame);
 
   // Helper method for adding a frame to |ready_frames_|
   void AddReadyFrame(const scoped_refptr<VideoFrame>& frame);
 
   // Helper method that schedules an asynchronous read from the decoder as long
   // as there isn't a pending read and we have capacity.
+  void AttemptRead();
   void AttemptRead_Locked();
 
-  // Called when the VideoDecoder Flush() completes.
-  void OnDecoderFlushDone();
+  // Called when VideoDecoder::Reset() completes.
+  void OnDecoderResetDone();
 
   // Attempts to complete flushing and transition into the flushed state.
   void AttemptFlush_Locked();
 
   // Calculates the duration to sleep for based on |current_frame_|'s timestamp,
   // the next frame timestamp (may be NULL), and the provided playback rate.
   //
   // We don't use |playback_rate_| to avoid locking.
   base::TimeDelta CalculateSleepDuration(
       const scoped_refptr<VideoFrame>& next_frame,
@@ skipping 14 matching lines @@
   void InitializeNextDecoder(const scoped_refptr<DemuxerStream>& demuxer_stream,
                              scoped_ptr<VideoDecoderList> decoders);
 
   // Called when |decoder_| initialization completes.
   // |demuxer_stream| & |decoders| are used if initialization failed and
   // InitializeNextDecoder() needs to be called again.
   void OnDecoderInitDone(const scoped_refptr<DemuxerStream>& demuxer_stream,
                          scoped_ptr<VideoDecoderList> decoders,
                          PipelineStatus status);
 
+  scoped_refptr<base::MessageLoopProxy> message_loop_;
+
   // Used for accessing data members.
   base::Lock lock_;
 
   scoped_refptr<VideoDecoder> decoder_;
 
   // Queue of incoming frames as well as the current frame since the last time
   // OnFrameAvailable() was called.
   typedef std::deque<scoped_refptr<VideoFrame> > VideoFrameQueue;
   VideoFrameQueue ready_frames_;
 
@@ skipping 12 matching lines @@
 
   // Used to signal |thread_| as frames are added to |frames_|.  Rule of thumb:
   // always check |state_| to see if it was set to STOPPED after waking up!
   base::ConditionVariable frame_available_;
 
   // State transition Diagram of this class:
   //       [kUninitialized] -------> [kError]
   //              |
   //              | Initialize()
   //              V        All frames returned
-  //   +------[kFlushed]<-----[kFlushing]<--- OnDecoderFlushDone()
+  //   +------[kFlushed]<-----[kFlushing]<--- OnDecoderResetDone()
   //   |          | Preroll() or upon                  ^
   //   |          V got first frame           [kFlushingDecoder]
   //   |      [kPrerolling]                            ^
   //   |          |                                 | Flush()
   //   |          V Got enough frames               |
   //   |      [kPrerolled]---------------------->[kPaused]
   //   |          |                Pause()          ^
   //   |          V Play()                          |
   //   |       [kPlaying]---------------------------|
   //   |          |                Pause()          ^
@@ skipping 69 matching lines @@
 
   // The last natural size |size_changed_cb_| was called with.
   gfx::Size last_natural_size_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoRendererBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_VIDEO_RENDERER_BASE_H_