Implement video frame acknowledgements in the chromoting protocol.

remoting/host/video_scheduler.h

Index: remoting/host/video_scheduler.h
diff --git a/remoting/host/video_scheduler.h b/remoting/host/video_scheduler.h
index c30ffa25310c1b1062a758d531c35102d4b70623..59c1b01c9e2d7680b5b7560f108b8a3363cb599d 100644
--- a/remoting/host/video_scheduler.h
+++ b/remoting/host/video_scheduler.h
@@ -14,6 +14,7 @@
 #include "base/timer/timer.h"
 #include "remoting/codec/video_encoder.h"
 #include "remoting/proto/video.pb.h"
+#include "remoting/protocol/video_stub.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_capturer.h"
 #include "third_party/webrtc/modules/desktop_capture/mouse_cursor_monitor.h"
 
@@ -33,7 +34,6 @@ class CursorShapeInfo;
 namespace protocol {
 class CursorShapeInfo;
 class CursorShapeStub;
-class VideoStub;
 }  // namespace protocol
 
 // Class responsible for scheduling frame captures from a
@@ -130,7 +130,7 @@ class VideoScheduler : public base::RefCountedThreadSafe<VideoScheduler>,
                              const webrtc::DesktopVector& position) override;
 
   // Starts the capturer on the capture thread.
-  void StartOnCaptureThread();
+  void StartOnCaptureThread(bool acks_supported);
 
   // Stops scheduling frame captures on the capture thread.
   void StopOnCaptureThread();
@@ -144,20 +144,23 @@ class VideoScheduler : public base::RefCountedThreadSafe<VideoScheduler>,
   // Called when a frame has been sent to the client.
   void ProcessFrameSentOnCaptureThread();
 
+  // Called when a frame has been sent to the client.
+  void ProcessFrameAckOnCaptureThread();
+
   // Network thread -----------------------------------------------------------
 
   // Send |packet| to the client, unless we are in the process of stopping.
   void SendVideoPacket(scoped_ptr<VideoPacket> packet);
 
-  // Callback passed to |video_stub_| for the last packet in each frame, to
+  // Callback passed to |video_stub_|, to
   // rate-limit frame captures to network throughput.
-  void OnVideoPacketSent();
+  void OnVideoPacketProgress(protocol::VideoStub::PacketProgress progress);
 
   // Called by |keep_alive_timer_|.
   void SendKeepAlivePacket();
 
   // Callback for |video_stub_| called after a keep-alive packet is sent.
-  void OnKeepAlivePacketSent();
+  void OnKeepAlivePacketProgress(protocol::VideoStub::PacketProgress progress);
 
   // Send updated cursor shape to client.
   void SendCursorShape(scoped_ptr<protocol::CursorShapeInfo> cursor_shape);