Pass camera facing info to audio client

content/browser/renderer_host/media/media_stream_manager.h

Index: content/browser/renderer_host/media/media_stream_manager.h
diff --git a/content/browser/renderer_host/media/media_stream_manager.h b/content/browser/renderer_host/media/media_stream_manager.h
index 8747539857459c586e05796386bea7f8223dc1c1..0ec39219da854e695c09612ca9bac9d7fe4df0c9 100644
--- a/content/browser/renderer_host/media/media_stream_manager.h
+++ b/content/browser/renderer_host/media/media_stream_manager.h
@@ -45,6 +45,7 @@
 #include "content/common/media/media_devices.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/public/browser/media_request_state.h"
+#include "media/base/video_facing.h"
 
 namespace media {
 class AudioManager;
@@ -97,6 +98,16 @@ class CONTENT_EXPORT MediaStreamManager
   // Used to access MediaDevicesManager.
   MediaDevicesManager* media_devices_manager();
 
+  // AddVideoCaptureObserver() and RemoveAllVideoCaptureObservers() should be
+  // called after InitializeDeviceManagersOnIOThread() and before
+  // WillDestroyCurrentMessageLoop(). They can be called more than once and it's
+  // ok to not call at all if the client is not interested in receiving
+  // media::VideoCaptureObserver callacks.
+  // The methods can be called on whatever thread. The callbacks of
+  // media::VideoCaptureObserver arrive on BrowserThread::IO.
+  void AddVideoCaptureObserver(media::VideoCaptureObserver* capture_observer);
+  void RemoveAllVideoCaptureObservers();
+
   // Creates a new media access request which is identified by a unique string
   // that's returned to the caller. This will trigger the infobar and ask users
   // for access to the device. |render_process_id| and |render_frame_id| are