Implicit audio output device selection for getUserMedia.

content/renderer/media/webrtc_local_audio_renderer.h

Index: content/renderer/media/webrtc_local_audio_renderer.h
diff --git a/content/renderer/media/webrtc_local_audio_renderer.h b/content/renderer/media/webrtc_local_audio_renderer.h
index f58aee3c29390461e634cef8553e24d78f9a10d0..f77d523f4a6dc8413b51624f546e73537fb1ed14 100644
--- a/content/renderer/media/webrtc_local_audio_renderer.h
+++ b/content/renderer/media/webrtc_local_audio_renderer.h
@@ -48,7 +48,10 @@ class CONTENT_EXPORT WebRtcLocalAudioRenderer
   // The |source| is owned by the WebRtcAudioDeviceImpl.
   // Called on the main thread.
   WebRtcLocalAudioRenderer(WebRtcLocalAudioTrack* audio_track,
-                           int source_render_view_id);
+                           int source_render_view_id,
+                           int session_id,
+                           int sample_rate,
+                           int frames_per_buffer);
 
   // MediaStreamAudioRenderer implementation.
   // Called on the main thread.
@@ -101,6 +104,7 @@ class CONTENT_EXPORT WebRtcLocalAudioRenderer
 
   // The render view in which the audio is rendered into |sink_|.
   const int source_render_view_id_;
+  const int session_id_;
 
   // The sink (destination) for rendered audio.
   scoped_refptr<media::AudioOutputDevice> sink_;
@@ -128,6 +132,14 @@ class CONTENT_EXPORT WebRtcLocalAudioRenderer
   // Protects |loopback_fifo_|, |playing_| and |sink_|.
   mutable base::Lock thread_lock_;
 
+  // The preferred sample rate and buffer sizes provided via the ctor.
+  const int sample_rate_;
+  const int frames_per_buffer_;
+
+  // The preferred device id of the output device or empty for the default
+  // output device.
+  const std::string output_device_id_;
+
   DISALLOW_COPY_AND_ASSIGN(WebRtcLocalAudioRenderer);
 };