Replace AudioSilenceDetector with an AudioPowerMonitor.

content/browser/renderer_host/media/audio_renderer_host.h

Index: content/browser/renderer_host/media/audio_renderer_host.h
diff --git a/content/browser/renderer_host/media/audio_renderer_host.h b/content/browser/renderer_host/media/audio_renderer_host.h
index ef257b20cd6e45d7d58ab524cee21d26ebf47143..2bb597a1b1b267d476687031ab50d187cd4634eb 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.h
+++ b/content/browser/renderer_host/media/audio_renderer_host.h
@@ -42,7 +42,6 @@
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/memory/shared_memory.h"
 #include "base/process.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "content/common/content_export.h"
@@ -123,10 +122,10 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
   // Complete the process of creating an audio stream. This will set up the
   // shared memory or shared socket in low latency mode and send the
   // NotifyStreamCreated message to the peer.
-  void DoCompleteCreation(AudioEntry* entry);
+  void DoCompleteCreation(int stream_id);
 
-  // Propagate audible signal to MediaObserver.
-  void DoNotifyAudibleState(AudioEntry* entry, bool is_audible);
+  // Propagate measured power level of the audio signal to MediaObserver.
+  void DoNotifyAudioPowerLevel(int stream_id, float power_dbfs, bool clipped);
 
   // Send an error message to the renderer.
   void SendErrorMessage(int stream_id);