Introduce AudioHardwareConfig for renderer side audio device info.

content/renderer/media/audio_renderer_mixer_manager.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 CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_
 #define CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_
 
 #include <map>
 #include <utility>
 
 #include "base/synchronization/lock.h"
 #include "content/common/content_export.h"
 #include "media/audio/audio_parameters.h"
 
 namespace media {
+class AudioHardwareConfig;
 class AudioRendererMixer;
 class AudioRendererMixerInput;
 class AudioRendererSink;
 }
 
 namespace content {
 
 // Manages sharing of an AudioRendererMixer among AudioRendererMixerInputs based
 // on their AudioParameters configuration.  Inputs with the same AudioParameters
 // configuration will share a mixer while a new AudioRendererMixer will be
 // lazily created if one with the exact AudioParameters does not exist.
 //
 // There should only be one instance of AudioRendererMixerManager per render
 // thread.
 //
 // TODO(dalecurtis): Right now we require AudioParameters to be an exact match
 // when we should be able to ignore bits per channel since we're only dealing
 // with floats.  However, bits per channel is currently used to interleave the
 // audio data by AudioOutputDevice::AudioThreadCallback::Process for consumption
 // via the shared memory.  See http://crbug.com/114700.
 class CONTENT_EXPORT AudioRendererMixerManager {
  public:
   // Construct an instance using the given audio hardware configuration.
-  AudioRendererMixerManager(int hardware_sample_rate, int hardware_buffer_size);
+  AudioRendererMixerManager(media::AudioHardwareConfig* hardware_config);

[scherkus (not reviewing), 2013/01/31 02:33:33]

raw pointer scares me -- care to document the lifetime + ownership situation?

[miu, 2013/01/31 05:28:53]

Drive-by comment: Add 'explicit' keyword here.

[DaleCurtis, 2013/01/31 19:50:00]

Done.

[DaleCurtis, 2013/01/31 19:50:00]

Done.

   ~AudioRendererMixerManager();
 
   // Creates an AudioRendererMixerInput with the proper callbacks necessary to
   // retrieve an AudioRendererMixer instance from AudioRendererMixerManager.
   // |source_render_view_id| refers to the RenderView containing the entity
   // rendering the audio.  Caller must ensure AudioRendererMixerManager outlives
   // the returned input.
   media::AudioRendererMixerInput* CreateInput(int source_render_view_id);
 
  private:
@@ skipping 25 matching lines @@
   // this method when it's done with a mixer.
   void RemoveMixer(int source_render_view_id,
                    const media::AudioParameters& params);
 
   // Active mixers.
   AudioRendererMixerMap mixers_;
   base::Lock mixers_lock_;
 
   // Audio hardware configuration.  Used to construct output AudioParameters for
   // each AudioRendererMixer instance.
-  int hardware_sample_rate_;
-  int hardware_buffer_size_;
+  media::AudioHardwareConfig* const hardware_config_;
 
   media::AudioRendererSink* sink_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererMixerManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_