Introduce media::TimeSource.

media/base/video_renderer.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_BASE_VIDEO_RENDERER_H_
 #define MEDIA_BASE_VIDEO_RENDERER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
@@ skipping 17 matching lines @@
 
   VideoRenderer();
   virtual ~VideoRenderer();
 
   // Initialize a VideoRenderer with |stream|, executing |init_cb| upon
   // completion.
   //
   // |statistics_cb| is executed periodically with video rendering stats, such
   // as dropped frames.
   //
-  // |time_cb| is executed whenever time has advanced by way of video rendering.
-  //
   // |buffering_state_cb| is executed when video rendering has either run out of
   // data or has enough data to continue playback.
   //
   // |ended_cb| is executed when video rendering has reached the end of stream.
   //
   // |error_cb| is executed if an error was encountered.
   //
   // |get_time_cb| is used to query the current media playback time.
   //
   // |get_duration_cb| is used to query the media duration.
   virtual void Initialize(DemuxerStream* stream,
                           bool low_delay,
                           const PipelineStatusCB& init_cb,
                           const StatisticsCB& statistics_cb,
-                          const TimeCB& time_cb,
                           const BufferingStateCB& buffering_state_cb,
                           const base::Closure& ended_cb,
                           const PipelineStatusCB& error_cb,
                           const TimeDeltaCB& get_time_cb,
                           const TimeDeltaCB& get_duration_cb) = 0;
 
   // Discard any video data and stop reading from |stream|, executing |callback|
   // when completed.
   //
   // Clients should expect |buffering_state_cb| to be called with
   // BUFFERING_HAVE_NOTHING while flushing is in progress.
   virtual void Flush(const base::Closure& callback) = 0;
 
   // Starts playback by reading from |stream| and decoding and rendering video.
-  // |timestamp| is the media timestamp playback should start rendering from.
   //
   // Only valid to call after a successful Initialize() or Flush().
-  virtual void StartPlayingFrom(base::TimeDelta timestamp) = 0;
+  virtual void StartPlaying() = 0;
 
   // Stop all operations in preparation for being deleted, executing |callback|
   // when complete.
   virtual void Stop(const base::Closure& callback) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(VideoRenderer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_RENDERER_H_