ChannelProxy: Send() from UI thread when ChannelMojo is used.

ipc/mojo/ipc_message_pipe_reader.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 IPC_IPC_MESSAGE_PIPE_READER_H_
 #define IPC_IPC_MESSAGE_PIPE_READER_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/task_runner.h"
 #include "ipc/ipc_message.h"
 #include "mojo/public/c/environment/async_waiter.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace IPC {
 namespace internal {
 
 // A helper class to handle bytestream directly over mojo::MessagePipe
 // in template-method pattern. MessagePipeReader manages the lifetime
 // of given MessagePipe and participates the event loop, and
@@ skipping 51 matching lines @@
     handle_buffer_.swap(*handle_buffer);
   }
 
   // Close and destroy the MessagePipe.
   void Close();
   // Close the mesage pipe with notifying the client with the error.
   void CloseWithError(MojoResult error);
   // Return true if the MessagePipe is alive.
   bool IsValid() { return pipe_.is_valid(); }
 
-  bool Send(scoped_ptr<Message> message);
+  // |Send()| doesn't notify error nor close the message pipe. The caller must
+  // handle the error if the return value isn't |MOJO_RESULT_OK|. This policy
+  // gives some flexibility when to do the error notification.
+  MojoResult Send(scoped_ptr<Message> message);
 
  private:
   static void InvokePipeIsReady(void* closure, MojoResult result);
 
   void OnMessageReceived();
   void OnPipeClosed();
   void OnPipeError(MojoResult error);
 
   MojoResult ReadMessageBytes();
   void PipeIsReady(MojoResult wait_result);
   void StartWaiting();
   void StopWaiting();
 
   std::vector<char>  data_buffer_;
   std::vector<MojoHandle> handle_buffer_;
   MojoAsyncWaitID pipe_wait_id_;
   mojo::ScopedMessagePipeHandle pipe_;
   // Is null once the message pipe is closed.
   Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePipeReader);
 };
 
 }  // namespace internal
 }  // namespace IPC
 
 #endif  // IPC_IPC_MESSAGE_PIPE_READER_H_