Convert some audio code to OnceCallback.

media/audio/audio_output_controller.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 MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include <stdint.h>
 #include <memory>
 #include <set>
@@ skipping 125 matching lines @@
   void Pause();
 
   // Closes the audio output stream. The state is changed and the resources
   // are freed on the audio manager thread. |closed_task| is executed after
   // that, on the thread on which Close was called. Callbacks (EventHandler and
   // SyncReader) must exist until closed_task is called, but they are safe
   // to delete after that.
   //
   // It is safe to call this method more than once. Calls after the first one
   // will have no effect.
-  void Close(const base::Closure& closed_task);
+  void Close(base::OnceClosure closed_task);
 
   // Sets the volume of the audio output stream.
   void SetVolume(double volume);
 
   // AudioSourceCallback implementation.
   int OnMoreData(base::TimeDelta delay,
                  base::TimeTicks delay_timestamp,
                  int prior_frames_skipped,
                  AudioBus* dest) override;
   void OnError(AudioOutputStream* stream) override;
@@ skipping 109 matching lines @@
   // be accessed while |error_lock_| is held.
   bool ignore_errors_during_stop_close_;
   base::Lock error_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_