Replace AudioSilenceDetector with an AudioPowerMonitor.

media/audio/audio_output_controller.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_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include "base/atomic_ref_count.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
@@ skipping 34 matching lines @@
 // all functionally equivalent and require a Play() call to continue to the next
 // state.
 //
 // The AudioOutputStream can request data from the AudioOutputController via the
 // AudioSourceCallback interface. AudioOutputController uses the SyncReader
 // passed to it via construction to synchronously fulfill this read request.
 //
 
 namespace media {
 
-class AudioSilenceDetector;
+class AudioPowerMonitor;

[Chris Rogers, 2013/07/18 00:09:36]

sss

 
 class MEDIA_EXPORT AudioOutputController
     : public base::RefCountedThreadSafe<AudioOutputController>,
       public AudioOutputStream::AudioSourceCallback,
       public AudioSourceDiverter,
       NON_EXPORTED_BASE(public AudioManager::AudioDeviceListener)  {
  public:
   // An event handler that receives events from the AudioOutputController. The
   // following methods are called on the audio manager thread.
   class MEDIA_EXPORT EventHandler {
    public:
     virtual void OnCreated() = 0;
     virtual void OnPlaying() = 0;
-    virtual void OnAudible(bool is_audible) = 0;
+    virtual void OnPowerMeasured(float power_dbfs, bool clipped) = 0;
     virtual void OnPaused() = 0;
     virtual void OnError() = 0;
     virtual void OnDeviceChange(int new_buffer_size, int new_sample_rate) = 0;
 
    protected:
     virtual ~EventHandler() {}
   };
 
   // A synchronous reader interface used by AudioOutputController for
   // synchronous reading.
@@ skipping 147 matching lines @@
   SyncReader* const sync_reader_;
 
   // The message loop of audio manager thread that this object runs on.
   const scoped_refptr<base::MessageLoopProxy> message_loop_;
 
   // When starting stream we wait for data to become available.
   // Number of times left.
   int number_polling_attempts_left_;
 
   // 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);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_