Mojo: Add Channel::AttachEndpoint(), which takes a ChannelEndpoint.

mojo/system/proxy_message_pipe_endpoint.h

 // Copyright 2013 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 MOJO_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_
 #define MOJO_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_
 
-#include <stdint.h>
-
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "mojo/system/message_in_transit.h"
 #include "mojo/system/message_in_transit_queue.h"
 #include "mojo/system/message_pipe_endpoint.h"
 #include "mojo/system/system_impl_export.h"
 
 namespace mojo {
 namespace system {
 
@@ skipping 56 matching lines @@
   // not ready to send them yet.
   MessageInTransitQueue paused_message_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyMessagePipeEndpoint);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_