Remove unused VideoFrameCapturer::size_most_recent() method.

remoting/capturer/video_frame_capturer.h

Index: remoting/capturer/video_frame_capturer.h
diff --git a/remoting/capturer/video_frame_capturer.h b/remoting/capturer/video_frame_capturer.h
index d126126dedf41627f276c8a18db66bee5aac627b..f16616bc8085c9d867a5e5fa64dbfbe719715b03 100644
--- a/remoting/capturer/video_frame_capturer.h
+++ b/remoting/capturer/video_frame_capturer.h
@@ -107,9 +107,6 @@ class VideoFrameCapturer {
   // data of the previous capture. There can be at most one concurrent read
   // going on when this method is called.
   virtual void CaptureFrame() = 0;
-
-  // Get the size of the most recently captured screen.
-  virtual const SkISize& size_most_recent() const = 0;
 };
 
 }  // namespace remoting