Caching AudioOutputDevice instances in mixer manager

content/renderer/media/audio_renderer_mixer_manager.h

Index: content/renderer/media/audio_renderer_mixer_manager.h
diff --git a/content/renderer/media/audio_renderer_mixer_manager.h b/content/renderer/media/audio_renderer_mixer_manager.h
index 20a1aa59eaf3db3d8e65c0ef805dfe98c16e5e9e..96bbc72a0212709d75a035c12f3bef5b14500d2a 100644
--- a/content/renderer/media/audio_renderer_mixer_manager.h
+++ b/content/renderer/media/audio_renderer_mixer_manager.h
@@ -6,8 +6,8 @@
 #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"
@@ -18,13 +18,12 @@
 #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
@@ -41,7 +40,8 @@ namespace content {
 // 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
@@ -74,6 +74,16 @@ class CONTENT_EXPORT AudioRendererMixerManager {
                    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;
 
@@ -135,6 +145,9 @@ class CONTENT_EXPORT AudioRendererMixerManager {
   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);
 };