Add CancelChannelCreation() in protocol::Session interface.

remoting/protocol/connection_to_client.cc

 // Copyright (c) 2011 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.
 
 #include "remoting/protocol/connection_to_client.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/message_loop_proxy.h"
 #include "google/protobuf/message.h"
@@ skipping 144 matching lines @@
   if (control_connected_ && input_connected_ && video_connected_)
     handler_->OnConnectionOpened(this);
 }
 
 void ConnectionToClient::CloseOnError() {
   CloseChannels();
   handler_->OnConnectionFailed(this);
 }
 
 void ConnectionToClient::CloseChannels() {
-  if (video_writer_.get())
-    video_writer_->Close();
-  if (client_control_sender_.get())
-    client_control_sender_->Close();
+  video_writer_.reset();
+  client_control_sender_.reset();
+  dispatcher_.reset();
 }
 
 }  // namespace protocol
 }  // namespace remoting