WebContentsAudioMuter: Mute all audio output from a WebContentsImpl.

content/public/browser/web_contents.h

Index: content/public/browser/web_contents.h
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index b62e9546d38673f5c142b9366848bd223e80a25d..b62cc0f17b1a35790421641550cd5433621829bb 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -306,6 +306,10 @@ class WebContents : public PageNavigator,
   virtual void DecrementCapturerCount() = 0;
   virtual int GetCapturerCount() const = 0;
 
+  // Indicates/Sets whether all audio output from this WebContents is muted.
+  virtual bool IsAudioMuted() const = 0;
+  virtual void ToggleAudioMute(bool mute) = 0;

[Avi (use Gerrit), 2014/09/21 00:20:00]

"Toggle" means to switch between two settings (without taking a new setting
value as a parameter), so this isn't a correct use of the word. Perhaps
"SetAudioMuted(bool mute)" to match "IsAudioMuted"?

[miu, 2014/09/21 02:33:33]

Done.

+
   // Indicates whether this tab should be considered crashed. The setter will
   // also notify the delegate when the flag is changed.
   virtual bool IsCrashed() const  = 0;