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

media/base/pipeline.h

Index: media/base/pipeline.h
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index 6a408da23f0d18abaa66411044e58d37d6e29ecb..9bfa7857a9522455d1e7960d6b3c4e439d15e677 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -34,6 +34,7 @@ class MediaLog;
 class TextRenderer;
 class TextTrackConfig;
 class TimeDeltaInterpolator;
+class TimeSource;
 class VideoRenderer;
 
 // Metadata describing a pipeline once it has been initialized.
@@ -317,7 +318,7 @@ class MEDIA_EXPORT Pipeline : public DemuxerHost {
   void PausePlayback();
   void StartPlayback();
 
-  void PauseClockAndStopRendering_Locked();
+  void PauseClockAndStopTicking_Locked();
   void StartClockIfWaitingForTimeUpdate_Locked();
 
   // Task runner used to execute pipeline tasks.
@@ -420,6 +421,9 @@ class MEDIA_EXPORT Pipeline : public DemuxerHost {
   scoped_ptr<VideoRenderer> video_renderer_;
   scoped_ptr<TextRenderer> text_renderer_;
 
+  // Renderer-provided time source used to control playback.
+  TimeSource* time_source_;
+
   PipelineStatistics statistics_;
 
   scoped_ptr<SerialRunner> pending_callbacks_;