Cleaned up the WebRtcAudioCapturer a bit.

content/renderer/media/webrtc_audio_device_impl.h

Index: content/renderer/media/webrtc_audio_device_impl.h
diff --git a/content/renderer/media/webrtc_audio_device_impl.h b/content/renderer/media/webrtc_audio_device_impl.h
index 1d904fa496202277130bc900edb0aea72b525472..f9279f5f6ff5c4986b1afd62e5223228426ae690 100644
--- a/content/renderer/media/webrtc_audio_device_impl.h
+++ b/content/renderer/media/webrtc_audio_device_impl.h
@@ -299,14 +299,21 @@ class CONTENT_EXPORT WebRtcAudioDeviceImpl
   // Called on the main renderer thread.
   bool SetAudioRenderer(WebRtcAudioRenderer* renderer);
 
-  // Adds the capturer to the ADM.
+  // Adds/Removes the capturer to the ADM.
+  // TODO(xians): Remove these two methods once the ADM does not need to pass
+  // hardware information up to WebRtc.
   void AddAudioCapturer(const scoped_refptr<WebRtcAudioCapturer>& capturer);
-
-  // Gets the default capturer, which is the capturer in the list with
-  // a valid |device_id|. Microphones are represented by capturers with a valid
-  // |device_id|, since only one microphone is supported today, only one
-  // capturer in the |capturers_| can have a valid |device_id|.
-  scoped_refptr<WebRtcAudioCapturer> GetDefaultCapturer() const;
+  void RemoveAudioCapturer(const scoped_refptr<WebRtcAudioCapturer>& capturer);
+
+  // Gets paired device information of the capture device for the audio
+  // renderer. This is used to pass on a session id, sample rate and buffer
+  // size to a webrtc audio renderer (either local or remote), so that audio
+  // will be rendered to a matching output device.
+  // Returns true if the capture device has a paired output device, otherwise
+  // false. Note that if there are more than one open capture device 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);
 
   const scoped_refptr<WebRtcAudioRenderer>& renderer() const {
     return renderer_;
@@ -355,6 +362,10 @@ class CONTENT_EXPORT WebRtcAudioDeviceImpl
   virtual void SetRenderFormat(const media::AudioParameters& params) OVERRIDE;
   virtual void RemoveAudioRenderer(WebRtcAudioRenderer* renderer) OVERRIDE;
 
+  // Helper to get the default capturer, which is the last capturer in
+  // |capturers_|.
+  scoped_refptr<WebRtcAudioCapturer> GetDefaultCapturer() const;
+
   // Used to DCHECK that we are called on the correct thread.
   base::ThreadChecker thread_checker_;