Implement video frame acknowledgements in the chromoting protocol.

remoting/protocol/host_video_dispatcher.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_PROTOCOL_HOST_VIDEO_DISPATCHER_H_
 #define REMOTING_PROTOCOL_HOST_VIDEO_DISPATCHER_H_
 
+#include <deque>
 #include <string>
 
 #include "base/compiler_specific.h"
-#include "remoting/protocol/buffered_socket_writer.h"
+#include "remoting/proto/video.pb.h"
 #include "remoting/protocol/channel_dispatcher_base.h"
-#include "remoting/protocol/video_stub.h"
+#include "remoting/protocol/protobuf_message_parser.h"
+#include "remoting/protocol/video_sender.h"
 
 namespace remoting {
 namespace protocol {
 
-class HostVideoDispatcher : public ChannelDispatcherBase, public VideoStub {
+class HostVideoDispatcher : public ChannelDispatcherBase, public VideoSender {
  public:
   HostVideoDispatcher();
   ~HostVideoDispatcher() override;
 
   // VideoStub interface.
   void ProcessVideoPacket(scoped_ptr<VideoPacket> packet,
                           const base::Closure& done) override;
+  bool SupportsAcks() override;
 
  private:
+  struct PendingFrame {
+    PendingFrame(int frame_id, const base::Closure& done);
+
+    int32_t frame_id;
+    base::Closure done;
+  };
+
+  void OnVideoAck(scoped_ptr<VideoAck> ack, const base::Closure& done);
+
+  int32_t frame_id_;
+  ProtobufMessageParser<VideoAck> parser_;
+
+  std::deque<PendingFrame> pending_frames_;
+
   DISALLOW_COPY_AND_ASSIGN(HostVideoDispatcher);
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_HOST_VIDEO_DISPATCHER_H_