Attempt to fix audio wedges by restarting all streams.

media/audio/audio_output_dispatcher.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.
 
 // AudioOutputDispatcher is a single-threaded base class that dispatches
 // creation and deletion of audio output streams. AudioOutputProxy objects use
 // this class to allocate and recycle actual audio output streams. When playback
 // is started, the proxy calls StartStream() to get an output stream that it
 // uses to play audio. When playback is stopped, the proxy returns the stream
 // back to the dispatcher by calling StopStream().
@@ skipping 48 matching lines @@
   // Called by AudioOutputProxy when the volume is set.
   virtual void StreamVolumeSet(AudioOutputProxy* stream_proxy,
                                double volume) = 0;
 
   // Called by AudioOutputProxy when the stream is closed.
   virtual void CloseStream(AudioOutputProxy* stream_proxy) = 0;
 
   // Called on the audio thread when the AudioManager is shutting down.
   virtual void Shutdown() = 0;
 
+  // Called by the AudioManager to restart streams when a wedge is detected.  A
+  // wedge means the OS failed to request any audio after StartStream().  When a
+  // wedge is detected all streams across all dispatchers must be closed.  After
+  // all streams are closed, streams are restarted.  See http://crbug.com/160920
+  virtual void CloseStreamsForWedgeFix() = 0;
+  virtual void RestartStreamsForWedgeFix() = 0;
+
   // Accessor to the input device id used by unified IO.
   const std::string& input_device_id() const { return input_device_id_; }
 
  protected:
   friend class base::RefCountedThreadSafe<AudioOutputDispatcher>;
   friend class AudioOutputProxyTest;
 
   virtual ~AudioOutputDispatcher();
 
   // A no-reference-held pointer (we don't want circular references) back to the
   // AudioManager that owns this object.
   AudioManager* audio_manager_;
   const scoped_refptr<base::MessageLoopProxy> message_loop_;
   const AudioParameters params_;
   std::string output_device_id_;
   const std::string input_device_id_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcher);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_H_