Refactor VideoRendererImpl to use VideoFrameScheduler.

media/filters/video_frame_scheduler.h

 // Copyright 2014 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_FRAME_SCHEDULER_H_
 #define MEDIA_FILTERS_VIDEO_FRAME_SCHEDULER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
+#include "base/time/time.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 class VideoFrame;
 
 // Defines an abstract video frame scheduler that is capable of managing the
 // display of video frames at explicit times.
 class MEDIA_EXPORT VideoFrameScheduler {
  public:
   VideoFrameScheduler() {}
   virtual ~VideoFrameScheduler() {}
 
   enum Reason {
     DISPLAYED,  // Frame was displayed.
     DROPPED,    // Frame was dropped.
     RESET,      // Scheduler was reset before frame was scheduled for display.
   };
   typedef base::Callback<void(const scoped_refptr<VideoFrame>&, Reason)> DoneCB;
 
   // Schedule |frame| to be displayed at |wall_ticks|, firing |done_cb| when
   // the scheduler has finished with the frame.
   virtual void ScheduleVideoFrame(const scoped_refptr<VideoFrame>& frame,
                                   base::TimeTicks wall_ticks,
                                   const DoneCB& done_cb) = 0;
 
   // Causes the scheduler to release all previously scheduled frames. Frames
   // will be returned as RESET.
   virtual void Reset() = 0;

[acolwell GONE FROM CHROMIUM, 2014/04/24 16:43:59]

nit: You might want add a note here warning people that all |done_cb|s will be
dispatched within this call and callers should be careful about reentrancy
issues. If that is not the intended semantics then I think we should make sure
that all implementations do not dispatch the CBs within this call for consistant
behavior.

[scherkus (not reviewing), 2014/04/25 02:04:47]

Done.

 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_VIDEO_FRAME_SCHEDULER_H_