Implicit audio output device selection for getUserMedia.

content/renderer/media/media_stream_impl.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_MEDIA_STREAM_IMPL_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 137 matching lines @@
       webrtc::MediaStreamInterface* stream,
       const base::Closure& error_cb,
       const VideoFrameProvider::RepaintCB& repaint_cb);
   scoped_refptr<WebRtcAudioRenderer> CreateRemoteAudioRenderer(
       webrtc::MediaStreamInterface* stream);
   scoped_refptr<WebRtcLocalAudioRenderer> CreateLocalAudioRenderer(
       webrtc::MediaStreamInterface* stream);
 
   void StopLocalAudioTrack(const WebKit::WebMediaStream& web_stream);
 
+  // Returns a valid session id if a single capture device is currently open
+  // (and then the matching session_id), otherwise -1.
+  // This is used to pass on a session id to a webrtc audio renderer (either
+  // local or remote), so that audio will be rendered to a matching output
+  // device, should one exist.
+  // Note that if there are more than one open capture devices the function
+  // will not be able to pick an appropriate device and return false.
+  bool GetAuthorizedDeviceInfoForAudioRenderer(
+      int* session_id, int* output_sample_rate, int* output_buffer_size);
+
   // Weak ref to a MediaStreamDependencyFactory, owned by the RenderThread.
   // It's valid for the lifetime of RenderThread.
   MediaStreamDependencyFactory* dependency_factory_;
 
   // media_stream_dispatcher_ is a weak reference, owned by RenderView. It's
   // valid for the lifetime of RenderView.
   MediaStreamDispatcher* media_stream_dispatcher_;
 
   UserMediaRequests user_media_requests_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_IMPL_H_