Pass camera facing to WebKit

media/capture/video_capturer_source.h

Index: media/capture/video_capturer_source.h
diff --git a/media/capture/video_capturer_source.h b/media/capture/video_capturer_source.h
index 91879cfa7d7ca04bf754939bf7265168c7e4a82b..ddb6bfe4d00341b560b6a70d8b8949127085c871 100644
--- a/media/capture/video_capturer_source.h
+++ b/media/capture/video_capturer_source.h
@@ -114,6 +114,8 @@ class CAPTURE_EXPORT VideoCapturerSource {
   // may still occur after this call, so the caller must take care to
   // use refcounted or weak references in |new_frame_callback|.
   virtual void StopCapture() = 0;
+
+  virtual CameraFacing GetCameraFacing() const { return CameraFacing::DEFAULT; }
 };
 
 }  // namespace media