Caching AudioOutputDevice instances in mixer manager

media/audio/clockless_audio_sink.h

 // Copyright 2013 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_CLOCKLESS_AUDIO_SINK_H_
 #define MEDIA_AUDIO_CLOCKLESS_AUDIO_SINK_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "media/base/audio_renderer_sink.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace media {
 class AudioBus;
 class ClocklessAudioSinkThread;
 
 // Implementation of an AudioRendererSink that consumes the audio as fast as
 // possible. This class does not support multiple Play()/Pause() events.
 class MEDIA_EXPORT ClocklessAudioSink
     : NON_EXPORTED_BASE(public AudioRendererSink) {
  public:
   ClocklessAudioSink();
+  explicit ClocklessAudioSink(const OutputDeviceInfo& device_info);
 
   // AudioRendererSink implementation.
   void Initialize(const AudioParameters& params,
                   RenderCallback* callback) override;
   void Start() override;
   void Stop() override;
   void Pause() override;
   void Play() override;
   bool SetVolume(double volume) override;
   OutputDeviceInfo GetOutputDeviceInfo() override;
 
   // Returns the time taken to consume all the audio.
   base::TimeDelta render_time() { return playback_time_; }
 
   // Enables audio frame hashing.  Must be called prior to Initialize().
   void StartAudioHashForTesting();
 
   // Returns the hash of all audio frames seen since construction.
   std::string GetAudioHashForTesting();
 
  protected:
   ~ClocklessAudioSink() override;
 
  private:
+  const OutputDeviceInfo device_info_;
   std::unique_ptr<ClocklessAudioSinkThread> thread_;
   bool initialized_;
   bool playing_;
   bool hashing_;
 
   // Time taken in last set of Render() calls.
   base::TimeDelta playback_time_;
 
   DISALLOW_COPY_AND_ASSIGN(ClocklessAudioSink);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_CLOCKLESS_AUDIO_SINK_H_