Make tab audible and muted states and cause available for an extension API

content/public/browser/web_contents.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 CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 290 matching lines @@
   // of decrement calls.  |capture_size| specifies the capturer's video
   // resolution, but can be empty to mean "unspecified."  The first screen
   // capturer that provides a non-empty |capture_size| will override the value
   // returned by GetPreferredSize() until all captures have ended.
   virtual void IncrementCapturerCount(const gfx::Size& capture_size) = 0;
   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 SetAudioMuted(bool mute) = 0;
+  virtual void SetAudioMuted(bool muted, const std::string& cause) = 0;
+
+  // Get source (initial, user, capture, extensionid) for the tab's muted state
+  virtual const std::string& GetAudioMutedCause() const = 0;
 
   // 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;
   virtual void SetIsCrashed(base::TerminationStatus status, int error_code) = 0;
 
   virtual base::TerminationStatus GetCrashedStatus() const = 0;
 
   // Whether the tab is in the process of being destroyed.
   virtual bool IsBeingDestroyed() const = 0;
@@ skipping 282 matching lines @@
 
  private:
   // This interface should only be implemented inside content.
   friend class WebContentsImpl;
   WebContents() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_