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

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 813 matching lines @@
   }
 }
 
 // Called when the user clicks the tab audio indicator to mute the tab.
 - (void)toggleMute:(id)sender {
   DCHECK([sender isKindOfClass:[TabView class]]);
   NSInteger index = [self modelIndexForTabView:sender];
   if (!tabStripModel_->ContainsIndex(index))
     return;
   WebContents* contents = tabStripModel_->GetWebContentsAt(index);
-  chrome::SetTabAudioMuted(contents, !chrome::IsTabAudioMuted(contents));
+  chrome::SetTabAudioMuted(contents,
+                           !chrome::IsTabAudioMuted(contents),
+                           chrome::kUserMuteToggleCause);
 }
 
 // Called when the user closes a tab. Asks the model to close the tab. |sender|
 // is the TabView that is potentially going away.
 - (void)closeTab:(id)sender {
   DCHECK([sender isKindOfClass:[TabView class]]);
 
   // Cancel any pending tab transition.
   hoverTabSelector_->CancelTabTransition();
 
@@ skipping 1469 matching lines @@
   // up the hierarchy to the devtools container view to avoid that. Note that
   // the devtools view is always in the hierarchy even if it is not open or it
   // is detached.
   NSView* devtools_view = [[[view superview] superview] superview];
   if (devtools_view) {
     return [devtools_view convertRect:[devtools_view bounds] toView:nil];
   } else {
     return [view convertRect:[view bounds] toView:nil];
   }
 }