Replace AudioSilenceDetector with an AudioPowerMonitor.

media/audio/audio_output_controller.h

Index: media/audio/audio_output_controller.h
diff --git a/media/audio/audio_output_controller.h b/media/audio/audio_output_controller.h
index 0a83bae054c7c2ad3b52303454ed32d32a1119bc..453ea3831bf13940329c656fc82b57feffa7ef23 100644
--- a/media/audio/audio_output_controller.h
+++ b/media/audio/audio_output_controller.h
@@ -57,7 +57,7 @@
 
 namespace media {
 
-class AudioSilenceDetector;
+class AudioPowerMonitor;
 
 class MEDIA_EXPORT AudioOutputController
     : public base::RefCountedThreadSafe<AudioOutputController>,
@@ -71,7 +71,7 @@ class MEDIA_EXPORT AudioOutputController
    public:
     virtual void OnCreated() = 0;
     virtual void OnPlaying() = 0;
-    virtual void OnAudible(bool is_audible) = 0;
+    virtual void OnPowerMeasured(float power_in_dbfs) = 0;
     virtual void OnPaused() = 0;
     virtual void OnError() = 0;
     virtual void OnDeviceChange(int new_buffer_size, int new_sample_rate) = 0;
@@ -247,9 +247,9 @@ class MEDIA_EXPORT AudioOutputController
   base::WeakPtrFactory<AudioOutputController> weak_this_;
 
   // Scans audio samples from OnMoreIOData() as input and causes
-  // EventHandler::OnAudbile() to be called whenever a transition to a period of
-  // silence or non-silence is detected.
-  scoped_ptr<AudioSilenceDetector> silence_detector_;
+  // EventHandler::OnPowerMeasured() to be called with power level measurements
+  // at regular intervals.
+  scoped_ptr<AudioPowerMonitor> power_monitor_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };