Implement video frame acknowledgements in the chromoting protocol.

remoting/host/video_frame_pump.h

Index: remoting/host/video_frame_pump.h
diff --git a/remoting/host/video_frame_pump.h b/remoting/host/video_frame_pump.h
index 3b8d0f782713aa3dd697615d165f0ba51bceb7a7..025d79196ae1af36cdadccae32133ac7fa7ef60e 100644
--- a/remoting/host/video_frame_pump.h
+++ b/remoting/host/video_frame_pump.h
@@ -24,6 +24,7 @@ namespace remoting {
 class ScreenCapturerProxy;
 
 namespace protocol {
+class VideoFeedbackStub;
 class VideoStub;
 }  // namespace protocol
 
@@ -92,6 +93,10 @@ class VideoFramePump : public base::NonThreadSafe {
   void SetLosslessEncode(bool want_lossless);
   void SetLosslessColor(bool want_lossless);
 
+  protocol::VideoFeedbackStub* video_feedback_stub() {
+    return &capture_scheduler_;
+  }
+
  private:
   // Encodes and sends |frame|.
   void EncodeAndSendFrame(scoped_ptr<webrtc::DesktopFrame> frame);
@@ -101,8 +106,7 @@ class VideoFramePump : public base::NonThreadSafe {
                         base::TimeTicks timestamp,
                         scoped_ptr<VideoPacket> packet);
 
-  // Callback passed to |video_stub_| for the last packet in each frame, to
-  // rate-limit frame captures to network throughput.
+  // Callback passed to |video_stub_|.
   void OnVideoPacketSent();
 
   // Called by |keep_alive_timer_|.