Implement missing features in WebrtcVideoStream.

remoting/protocol/webrtc_video_capturer_adapter.h

Index: remoting/protocol/webrtc_video_capturer_adapter.h
diff --git a/remoting/protocol/webrtc_video_capturer_adapter.h b/remoting/protocol/webrtc_video_capturer_adapter.h
index 3c5375b439f18b93917193eff22f8a8c1799e4b0..2443475d727f5fb107077433eb85b5e23b826053 100644
--- a/remoting/protocol/webrtc_video_capturer_adapter.h
+++ b/remoting/protocol/webrtc_video_capturer_adapter.h
@@ -42,10 +42,14 @@ namespace protocol {
 class WebrtcVideoCapturerAdapter : public cricket::VideoCapturer,
                                    public webrtc::DesktopCapturer::Callback {
  public:
+  typedef base::Callback<void(const webrtc::DesktopSize& size)> SizeCallback;
+
   explicit WebrtcVideoCapturerAdapter(
       scoped_ptr<webrtc::DesktopCapturer> capturer);
   ~WebrtcVideoCapturerAdapter() override;
 
+  void SetSizeCallback(const SizeCallback& size_callback);
+
   // cricket::VideoCapturer implementation.
   bool GetBestCaptureFormat(const cricket::VideoFormat& desired,
                             cricket::VideoFormat* best_format) override;
@@ -70,6 +74,8 @@ class WebrtcVideoCapturerAdapter : public cricket::VideoCapturer,
 
   scoped_ptr<webrtc::DesktopCapturer> desktop_capturer_;
 
+  SizeCallback size_callback_;
+
   // Timer to call CaptureNextFrame().
   scoped_ptr<base::RepeatingTimer> capture_timer_;