Remove unused VideoFrameCapturer::size_most_recent() method.

remoting/capturer/video_frame_capturer_mac.mm

Index: remoting/capturer/video_frame_capturer_mac.mm
diff --git a/remoting/capturer/video_frame_capturer_mac.mm b/remoting/capturer/video_frame_capturer_mac.mm
index 8230c9b1b41fcd64523d3a6bc6bd033e56d8b976..8b10cac31431364ee152a0c1f24d7726823ccc2a 100644
--- a/remoting/capturer/video_frame_capturer_mac.mm
+++ b/remoting/capturer/video_frame_capturer_mac.mm
@@ -112,7 +112,6 @@ class VideoFrameCapturerMac : public VideoFrameCapturer {
   virtual void Stop() OVERRIDE;
   virtual void InvalidateRegion(const SkRegion& invalid_region) OVERRIDE;
   virtual void CaptureFrame() OVERRIDE;
-  virtual const SkISize& size_most_recent() const OVERRIDE;
 
  private:
   void CaptureCursor();
@@ -653,10 +652,6 @@ void VideoFrameCapturerMac::CgBlitPostLion(const VideoFrame& buffer,
   }
 }
 
-const SkISize& VideoFrameCapturerMac::size_most_recent() const {
-  return helper_.size_most_recent();
-}
-
 void VideoFrameCapturerMac::ScreenConfigurationChanged() {
   // Release existing buffers, which will be of the wrong size.
   ReleaseBuffers();