Add GetPreferredFormats method to media::VideoCapturerSource.

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..2cb9c02c963eb575e9719a15ac86f1a2510cacee 100644
--- a/media/capture/video_capturer_source.h
+++ b/media/capture/video_capturer_source.h
@@ -55,11 +55,16 @@ class CAPTURE_EXPORT VideoCapturerSource {
   // |max_requested_frame_rate| is used by Tab and Screen capture to decide what
   // resolution/framerate to generate. |callback| is triggered when the formats
   // have been collected.
+  // TODO(guidou): Remove this method. http://crbug.com/706408
   virtual void GetCurrentSupportedFormats(

[miu, 2017/04/05 20:58:36]

Does this still need to be a virtual method (are there overrides in subclasses)?

[Guido Urdaneta, 2017/04/05 21:14:59]

Yes, LocalVideoCapturerSource (defined in user_media_client_impl.cc) still has
an implementation of it, but we will remove the method in a future iteration
when we retire the old constraints algorithm.

       int max_requested_width,
       int max_requested_height,
       double max_requested_frame_rate,
-      const VideoCaptureDeviceFormatsCB& callback) = 0;
+      const VideoCaptureDeviceFormatsCB& callback);
+
+  // Returns formats that are preferred and can currently be used. May be empty
+  // if no formats are available or known.
+  virtual VideoCaptureFormats GetPreferredFormats() = 0;
 
   // Starts capturing frames using the capture |params|. |new_frame_callback| is
   // triggered when a new video frame is available.