Introduce AudioRendererSink::IsOptimizedForHardwareParameters

media/base/audio_renderer_sink.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_BASE_AUDIO_RENDERER_SINK_H_
 #define MEDIA_BASE_AUDIO_RENDERER_SINK_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 48 matching lines @@
   // Pauses playback.
   virtual void Pause() = 0;
 
   // Resumes playback after calling Pause().
   virtual void Play() = 0;
 
   // Sets the playback volume, with range [0.0, 1.0] inclusive.
   // Returns |true| on success.
   virtual bool SetVolume(double volume) = 0;
 
-  // Returns current output device information. If the information is not
+  // Returns current output device id and status with the optimal parameters
+  // given the sink's internal state. These may be the output device's
+  // parameters or the given |preferred_params|. If the information is not
   // available yet, this method may block until it becomes available.
   // If the sink is not associated with any output device, |device_status| of
   // OutputDeviceInfo should be set to OUTPUT_DEVICE_STATUS_ERROR_INTERNAL.
   // Must never be called on the IO thread.
-  virtual OutputDeviceInfo GetOutputDeviceInfo() = 0;
+  virtual OutputDeviceInfo GetOutputDeviceInfo(
+      const AudioParameters& preferred_params = AudioParameters()) = 0;

[o1ka, 2017/04/28 09:57:18]

What happens in the default case?
What if |preferred_params| are not default AudioParameters(), but invalid?

 
   // If DCHECKs are enabled, this function returns true if called on rendering
   // thread, otherwise false. With DCHECKs disabled, it returns true. Thus, it
   // is intended to be used for DCHECKing.
   virtual bool CurrentThreadIsRenderingThread() = 0;
 
  protected:
   friend class base::RefCountedThreadSafe<AudioRendererSink>;
   virtual ~AudioRendererSink() {}
 };
@@ skipping 19 matching lines @@
                                   const url::Origin& security_origin,
                                   const OutputDeviceStatusCB& callback) = 0;
 
  protected:
   ~SwitchableAudioRendererSink() override {}
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_RENDERER_SINK_H_