Caching AudioOutputDevice instances in mixer manager

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 <memory>
 #include <string>
-#include <utility>
 
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "content/common/content_export.h"
 #include "media/audio/audio_device_description.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/output_device_info.h"
 #include "url/origin.h"
 
 namespace media {
-class AudioHardwareConfig;
 class AudioRendererMixer;
 class AudioRendererMixerInput;
-class AudioRendererSink;
 }
 
 namespace content {
+class AudioRendererSinkCache;
 
 // 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:
-  AudioRendererMixerManager();
+  static std::unique_ptr<AudioRendererMixerManager> Create();
+
   ~AudioRendererMixerManager();
 
   // Creates an AudioRendererMixerInput with the proper callbacks necessary to
   // retrieve an AudioRendererMixer instance from AudioRendererMixerManager.
   // |source_render_frame_id| refers to the RenderFrame containing the entity
   // rendering the audio.  Caller must ensure AudioRendererMixerManager outlives
   // the returned input. |device_id|, |session_id| and |security_origin|
   // identify the output device to use. If |device_id| is empty and |session_id|
   // is nonzero, output device associated with the opened input device
   // designated by |session_id| is used. Otherwise, |session_id| is ignored.
@@ skipping 12 matching lines @@
                                       media::OutputDeviceStatus* device_status);
 
   // Remove a mixer instance given a mixer if the only other reference is held
   // by AudioRendererMixerManager.  Every AudioRendererMixer owner must call
   // this method when it's done with a mixer.
   void RemoveMixer(int source_render_frame_id,
                    const media::AudioParameters& params,
                    const std::string& device_id,
                    const url::Origin& security_origin);
 
+  // Returns output device information. This call goes to the sink cache.
+  media::OutputDeviceInfo GetOutputDeviceInfo(
+      int source_render_frame_id,
+      int session_id,
+      const std::string& device_id,
+      const url::Origin& security_origin);
+
+ protected:
+  AudioRendererMixerManager(std::unique_ptr<AudioRendererSinkCache> sink_cache);
+
  private:
   friend class AudioRendererMixerManagerTest;
 
   // Define a key so that only those AudioRendererMixerInputs from the same
   // RenderView, AudioParameters and output device can be mixed together.
   struct MixerKey {
     MixerKey(int source_render_frame_id,
              const media::AudioParameters& params,
              const std::string& device_id,
              const url::Origin& security_origin);
@@ skipping 41 matching lines @@
     media::AudioRendererMixer* mixer;
     int ref_count;
   };
   typedef std::map<MixerKey, AudioRendererMixerReference, MixerKeyCompare>
       AudioRendererMixerMap;
 
   // Active mixers.
   AudioRendererMixerMap mixers_;
   base::Lock mixers_lock_;
 
+  // Mixer sink cache. Should outlive |mixers_| => must be declared after them.
+  std::unique_ptr<AudioRendererSinkCache> sink_cache_;

[miu, 2016/05/12 21:53:06]

Please make this const, since it is not mutated any time after construction.

[o1ka, 2016/05/17 17:17:23]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(AudioRendererMixerManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_