Replace AudioSilenceDetector with an AudioPowerMonitor.

content/browser/renderer_host/media/audio_renderer_host.cc

Index: content/browser/renderer_host/media/audio_renderer_host.cc
diff --git a/content/browser/renderer_host/media/audio_renderer_host.cc b/content/browser/renderer_host/media/audio_renderer_host.cc
index 3b21720e9329a1ade901650de319590f030fae0b..75abb345169abbad0897d2437b0c3b90b0fa3f5b 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.cc
+++ b/content/browser/renderer_host/media/audio_renderer_host.cc
@@ -61,7 +61,7 @@ class AudioRendererHost::AudioEntry
   // media::AudioOutputController::EventHandler implementation.
   virtual void OnCreated() OVERRIDE;
   virtual void OnPlaying() OVERRIDE;
-  virtual void OnAudible(bool is_audible) OVERRIDE;
+  virtual void OnPowerMeasured(float power_in_dbfs) OVERRIDE;
   virtual void OnPaused() OVERRIDE;
   virtual void OnError() OVERRIDE;
   virtual void OnDeviceChange(int new_buffer_size, int new_sample_rate)
@@ -151,12 +151,12 @@ void AudioRendererHost::AudioEntry::OnPlaying() {
               stream_id_, media::AudioOutputIPCDelegate::kPlaying)));
 }
 
-void AudioRendererHost::AudioEntry::OnAudible(bool is_audible) {
+void AudioRendererHost::AudioEntry::OnPowerMeasured(float power_in_dbfs) {
   BrowserThread::PostTask(
       BrowserThread::IO,
       FROM_HERE,
-      base::Bind(&AudioRendererHost::DoNotifyAudibleState, host_,
-                 this, is_audible));
+      base::Bind(&AudioRendererHost::DoNotifyAudioPowerLevel, host_,
+                 this, power_in_dbfs));
 }
 
 void AudioRendererHost::AudioEntry::OnPaused() {
@@ -229,22 +229,22 @@ void AudioRendererHost::DoCompleteCreation(AudioEntry* entry) {
       media::PacketSizeInBytes(entry->shared_memory()->requested_size())));
 }
 
-void AudioRendererHost::DoNotifyAudibleState(AudioEntry* entry,
-                                             bool is_audible) {
+void AudioRendererHost::DoNotifyAudioPowerLevel(AudioEntry* entry,
+                                                float power_in_dbfs) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   MediaObserver* const media_observer =
       GetContentClient()->browser()->GetMediaObserver();
   if (media_observer) {
-    DVLOG(1) << "AudioRendererHost@" << this
-             << "::DoNotifyAudibleState(is_audible=" << is_audible
+    DVLOG(2) << "AudioRendererHost@" << this
+             << "::DoNotifyAudioPowerLevel(power_in_dbfs=" << power_in_dbfs
              << ") for stream_id=" << entry->stream_id();
 
     if (CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kEnableAudibleNotifications)) {
       media_observer->OnAudioStreamPlayingChanged(
           render_process_id_, entry->render_view_id(), entry->stream_id(),
-          is_audible);
+          true, power_in_dbfs);
     }
   }
 }
@@ -402,7 +402,8 @@ void AudioRendererHost::DeleteEntry(scoped_ptr<AudioEntry> entry) {
       GetContentClient()->browser()->GetMediaObserver();
   if (media_observer) {
     media_observer->OnAudioStreamPlayingChanged(
-        render_process_id_, entry->render_view_id(), entry->stream_id(), false);
+        render_process_id_, entry->render_view_id(), entry->stream_id(),
+        false, -std::numeric_limits<float>::infinity());
   }
 
   // Notify the media observer.