Tab audio mute control (views UI), behind a switch (off by default).

chrome/browser/ui/views/tabs/tab_strip.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 CHROME_BROWSER_UI_VIEWS_TABS_TAB_STRIP_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_TAB_STRIP_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
@@ skipping 195 matching lines @@
   void FileSupported(const GURL& url, bool supported);
 
   // TabController overrides:
   virtual const ui::ListSelectionModel& GetSelectionModel() OVERRIDE;
   virtual bool SupportsMultipleSelection() OVERRIDE;
   virtual void SelectTab(Tab* tab) OVERRIDE;
   virtual void ExtendSelectionTo(Tab* tab) OVERRIDE;
   virtual void ToggleSelected(Tab* tab) OVERRIDE;
   virtual void AddSelectionFromAnchorTo(Tab* tab) OVERRIDE;
   virtual void CloseTab(Tab* tab, CloseTabSource source) OVERRIDE;
+  virtual void ToggleTabAudioMute(Tab* tab) OVERRIDE;
   virtual void ShowContextMenuForTab(Tab* tab,
                                      const gfx::Point& p,
                                      ui::MenuSourceType source_type) OVERRIDE;
   virtual bool IsActiveTab(const Tab* tab) const OVERRIDE;
   virtual bool IsTabSelected(const Tab* tab) const OVERRIDE;
   virtual bool IsTabPinned(const Tab* tab) const OVERRIDE;
   virtual void MaybeStartDrag(
       Tab* tab,
       const ui::LocatedEvent& event,
       const ui::ListSelectionModel& original_selection) OVERRIDE;
@@ skipping 452 matching lines @@
   bool immersive_style_;
 
   // Our observers.
   typedef ObserverList<TabStripObserver> TabStripObservers;
   TabStripObservers observers_;
 
   DISALLOW_COPY_AND_ASSIGN(TabStrip);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_TAB_STRIP_H_