Plumb audio muting state to guest web-contents.

content/browser/web_contents/web_contents_impl.cc

 // 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.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 1110 matching lines @@
 
   if (mute) {
     if (!audio_muter_)
       audio_muter_.reset(new WebContentsAudioMuter(this));
     audio_muter_->StartMuting();
   } else {
     DCHECK(audio_muter_);
     audio_muter_->StopMuting();
   }
 
+  FOR_EACH_OBSERVER(WebContentsObserver, observers_,
+                    DidUpdateAudioMutingState(mute));
+
   // Notification for UI updates in response to the changed muting state.
   NotifyNavigationStateChanged(INVALIDATE_TYPE_TAB);
 }
 
 bool WebContentsImpl::IsCrashed() const {
   return (crashed_status_ == base::TERMINATION_STATUS_PROCESS_CRASHED ||
           crashed_status_ == base::TERMINATION_STATUS_ABNORMAL_TERMINATION ||
           crashed_status_ == base::TERMINATION_STATUS_PROCESS_WAS_KILLED ||
 #if defined(OS_CHROMEOS)
           crashed_status_ ==
@@ skipping 3595 matching lines @@
     const WebContentsObserver::MediaPlayerId& id) {
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, MediaStartedPlaying(id));
 }
 
 void WebContentsImpl::MediaStoppedPlaying(
     const WebContentsObserver::MediaPlayerId& id) {
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, MediaStoppedPlaying(id));
 }
 
 }  // namespace content