Fix stuck keys problem with Chromoting when host disconnects while keys are

remoting/protocol/input_sender.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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.
 
 // This stub is thread safe because of the use of BufferedSocketWriter.
 // BufferedSocketWriter buffers messages and send them on them right thread.
 
 #include "remoting/protocol/input_sender.h"
 
 #include "base/task.h"
 #include "remoting/proto/event.pb.h"
 #include "remoting/proto/internal.pb.h"
 #include "remoting/protocol/buffered_socket_writer.h"
 #include "remoting/protocol/util.h"
 
 namespace remoting {
 namespace protocol {
 
 InputSender::InputSender(base::MessageLoopProxy* message_loop,
                          net::Socket* socket)
     : buffered_writer_(new BufferedSocketWriter(message_loop)) {
   // TODO(garykac) Set write failed callback.
   DCHECK(socket);
   buffered_writer_->Init(socket, NULL);
 }
 
 InputSender::~InputSender() {
 }
 
 void InputSender::InjectKeyEvent(const KeyEvent* event, Task* done) {
+  DCHECK(done);
+
   EventMessage message;
   message.set_sequence_number(base::Time::Now().ToInternalValue());
   message.mutable_key_event()->CopyFrom(*event);
   buffered_writer_->Write(SerializeAndFrameMessage(message), done);
 }
 
 void InputSender::InjectMouseEvent(const MouseEvent* event, Task* done) {
+  DCHECK(done);
+
   EventMessage message;
   message.set_sequence_number(base::Time::Now().ToInternalValue());
   message.mutable_mouse_event()->CopyFrom(*event);
   buffered_writer_->Write(SerializeAndFrameMessage(message), done);
 }
 
 void InputSender::Close() {
   buffered_writer_->Close();
 }
 
 }  // namespace protocol
 }  // namespace remoting