WebContentsAudioMuter: Mute all audio output from a WebContentsImpl.

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index 134b8d8860b4d24bf5cf734fb16ecbec2f22636b..5c76a984d54e03ad9cb5a83162a7915e3bde6830 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -65,6 +65,7 @@ class SavePackage;
 class ScreenOrientationDispatcherHost;
 class SiteInstance;
 class TestWebContents;
+class WebContentsAudioMuter;
 class WebContentsDelegate;
 class WebContentsImpl;
 class WebContentsObserver;
@@ -246,6 +247,8 @@ class CONTENT_EXPORT WebContentsImpl
   virtual void IncrementCapturerCount(const gfx::Size& capture_size) OVERRIDE;
   virtual void DecrementCapturerCount() OVERRIDE;
   virtual int GetCapturerCount() const OVERRIDE;
+  virtual bool IsAudioMuted() const OVERRIDE;
+  virtual void SetAudioMuted(bool mute) OVERRIDE;
   virtual bool IsCrashed() const OVERRIDE;
   virtual void SetIsCrashed(base::TerminationStatus status,
                             int error_code) OVERRIDE;
@@ -1241,6 +1244,9 @@ class CONTENT_EXPORT WebContentsImpl
   // Monitors power levels for audio streams associated with this WebContents.
   AudioStreamMonitor audio_stream_monitor_;
 
+  // Created on-demand to mute all audio output from this WebContents.
+  scoped_ptr<WebContentsAudioMuter> audio_muter_;
+
   base::WeakPtrFactory<WebContentsImpl> loading_weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsImpl);