Switch to using media::TimeSource inside media::RendererImpl.

media/base/time_source.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_BASE_TIME_SOURCE_H_
 #define MEDIA_BASE_TIME_SOURCE_H_
 
 #include "base/time/time.h"
 #include "media/base/media_export.h"
 
@@ skipping 16 matching lines @@
   // Updates the current playback rate. It is expected that values from
   // CurrentMediaTime() will eventually reflect the new playback rate (e.g., the
   // media time will advance at half speed if the rate was set to 0.5f).
   virtual void SetPlaybackRate(float playback_rate) = 0;
 
   // Sets the media time to start ticking from. Only valid to call while the
   // time source is not ticking.
   virtual void SetMediaTime(base::TimeDelta time) = 0;
 
   // Returns the current media time.
+  //
+  // Values returned are intended for informational purposes, such as displaying
+  // UI with the current minute and second count. While it is guaranteed values
+  // will never go backwards, the frequency at which they update may be low.
   virtual base::TimeDelta CurrentMediaTime() = 0;
+
+  // Returns an approximation of the current media time.
+  //
+  // Values returned are intended for interal use only, such as synchronizing
+  // video to audio.
+  //
+  // TODO(scherkus): Replace with a method that returns wall clock time for a
+  // given media time for use with VideoFrameScheduler http://crbug.com/110814
+  virtual base::TimeDelta ApproximateCurrentMediaTime() = 0;

[xhwang, 2014/09/08 22:56:06]

As discussed offline, it's a bit confusing that the non-informational time (more
accurate?) is approximate. How about "RawCurrentMediaTime" or
"CurrentMediaTimeForSync"? Or maybe some comments would help.

[scherkus (not reviewing), 2014/09/09 18:17:18]

Done.

 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_TIME_SOURCE_H_