preparation for recycling buffer, patch 2

media/filters/video_renderer_base.h

 // Copyright (c) 2010 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.
 
 // 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, calling OnFrameAvailable() on subclasses to notify
 // when a frame is ready to display.
 //
 // The media filter methods Initialize(), Stop(), SetPlaybackRate() and Seek()
@@ skipping 28 matching lines @@
   // be NULL where the result is not needed.
   static bool ParseMediaFormat(
       const MediaFormat& media_format,
       VideoFrame::SurfaceType* surface_type_out,
       VideoFrame::Format* surface_format_out,
       int* width_out, int* height_out);
 
   // MediaFilter implementation.
   virtual void Play(FilterCallback* callback);
   virtual void Pause(FilterCallback* callback);
+  virtual void Flush(FilterCallback* callback);
   virtual void Stop(FilterCallback* callback);
   virtual void SetPlaybackRate(float playback_rate);
   virtual void Seek(base::TimeDelta time, FilterCallback* callback);
 
   // VideoRenderer implementation.
   virtual void Initialize(VideoDecoder* decoder, FilterCallback* callback);
   virtual bool HasEnded();
 
   // PlatformThread::Delegate implementation.
   virtual void ThreadMain();
@@ skipping 87 matching lines @@
   scoped_refptr<VideoFrame> current_frame_;
 
   // 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!
   ConditionVariable frame_available_;
 
   // Simple state tracking variable.
   enum State {
     kUninitialized,
     kPaused,
+    kFlushing,
     kSeeking,
     kPlaying,
     kEnded,
     kStopped,
     kError,
   };
   State state_;
 
   // Video thread handle.
   PlatformThreadHandle thread_;
 
   // Previous time returned from the pipeline.
   base::TimeDelta previous_time_;
 
   // Keeps track of our pending reads.  We *must* have no pending reads before
   // executing the pause callback, otherwise we breach the contract that all
   // filters are idling.
   //
   // We use size_t since we compare against std::deque::size().
   size_t pending_reads_;
   bool pending_paint_;
 
   float playback_rate_;
 
   // Filter callbacks.
-  scoped_ptr<FilterCallback> pause_callback_;
+  scoped_ptr<FilterCallback> flush_callback_;
   scoped_ptr<FilterCallback> seek_callback_;
 
   base::TimeDelta seek_timestamp_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoRendererBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_VIDEO_RENDERER_BASE_H_