Close the shared audio output device when the tab is closed.

content/renderer/media/media_stream_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/renderer/media/media_stream_impl.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 534 matching lines @@
             UTF16ToUTF8((*request_it)->web_stream.id()));
       } else {
         media_stream_dispatcher_->CancelGenerateStream(
             (*request_it)->request_id, AsWeakPtr());
       }
       request_it = user_media_requests_.erase(request_it);
     } else {
       ++request_it;
     }
   }
+
+  // Free the potentially-cached audio renderer.  If we don't do this, the
+  // audio device will be held open after the tab has been closed even though
+  // it's not being used.
+  WebRtcAudioDeviceImpl* audio_device =
+      dependency_factory_->GetWebRtcAudioDevice();
+  if (audio_device) {
+    scoped_refptr<WebRtcAudioRenderer> renderer(audio_device->renderer());
+    if (renderer.get()) {
+      renderer->Stop();  // This will clear the dependency factory's pointer.
+      DCHECK(!audio_device->renderer().get());
+    }
+  }
 }
 
 scoped_refptr<VideoFrameProvider>
 MediaStreamImpl::CreateVideoFrameProvider(
     webrtc::MediaStreamInterface* stream,
     const base::Closure& error_cb,
     const VideoFrameProvider::RepaintCB& repaint_cb) {
   if (stream->GetVideoTracks().empty())
     return NULL;
 
@@ skipping 119 matching lines @@
   }
 
   for (size_t i = 0; i < video_sources.size(); ++i) {
     video_sources[i].setReadyState(
             WebKit::WebMediaStreamSource::ReadyStateEnded);
     video_sources[i].setExtraData(NULL);
   }
 }
 
 }  // namespace content