Make media::AudioRenderer inherit from media::TimeSource.

media/filters/audio_renderer_impl.h

Index: media/filters/audio_renderer_impl.h
diff --git a/media/filters/audio_renderer_impl.h b/media/filters/audio_renderer_impl.h
index 6986562f22f6318b4a0109fb287ac86b093c080d..a0c5096355847f9371a9b2cf928d592161e8f062 100644
--- a/media/filters/audio_renderer_impl.h
+++ b/media/filters/audio_renderer_impl.h
@@ -34,6 +34,7 @@
 
 namespace base {
 class SingleThreadTaskRunner;
+class TickClock;
 }
 
 namespace media {
@@ -65,6 +66,13 @@ class MEDIA_EXPORT AudioRendererImpl
       AudioHardwareConfig* hardware_params);
   virtual ~AudioRendererImpl();
 
+  // TimeSource implementation.

[xhwang, 2014/07/21 22:10:06]

Since AudioRenderer inherits TimeSource, this is not necessarily true. Strictly
speaking this is included in AudioRenderer impl on l.77

+  virtual void StartTicking() OVERRIDE;
+  virtual void StopTicking() OVERRIDE;
+  virtual void SetPlaybackRate(float rate) OVERRIDE;
+  virtual void SetMediaTime(base::TimeDelta timestamp) OVERRIDE;
+  virtual base::TimeDelta CurrentMediaTime() OVERRIDE;
+
   // AudioRenderer implementation.
   virtual void Initialize(DemuxerStream* stream,
                           const PipelineStatusCB& init_cb,
@@ -73,15 +81,13 @@ class MEDIA_EXPORT AudioRendererImpl
                           const BufferingStateCB& buffering_state_cb,
                           const base::Closure& ended_cb,
                           const PipelineStatusCB& error_cb) OVERRIDE;
-  virtual void StartRendering() OVERRIDE;
-  virtual void StopRendering() OVERRIDE;
-  virtual void SetMediaTime(base::TimeDelta time) OVERRIDE;
   virtual void Flush(const base::Closure& callback) OVERRIDE;
   virtual void Stop(const base::Closure& callback) OVERRIDE;
-  virtual void SetPlaybackRate(float rate) OVERRIDE;
   virtual void StartPlaying() OVERRIDE;
   virtual void SetVolume(float volume) OVERRIDE;
 
+  void SetTickClockForTesting(scoped_ptr<base::TickClock> tick_clock);
+
  private:
   friend class AudioRendererImplTest;
 
@@ -217,6 +223,8 @@ class MEDIA_EXPORT AudioRendererImpl
   // Callback provided to Flush().
   base::Closure flush_cb_;
 
+  scoped_ptr<base::TickClock> tick_clock_;
+
   // After Initialize() has completed, all variables below must be accessed
   // under |lock_|. ------------------------------------------------------------
   base::Lock lock_;
@@ -242,6 +250,7 @@ class MEDIA_EXPORT AudioRendererImpl
   bool rendered_end_of_stream_;
 
   scoped_ptr<AudioClock> audio_clock_;
+  base::TimeTicks last_render_ticks_;
 
   base::TimeDelta start_timestamp_;