Reland "Mojo C++ bindings: support sync methods - part 2"

mojo/public/cpp/bindings/message.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 MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 104 matching lines @@
 
   // A variant on Accept that registers a MessageReceiver (known as the
   // responder) to handle the response message generated from the given
   // message. The responder's Accept method may be called during
   // AcceptWithResponder or some time after its return.
   //
   // NOTE: Upon returning true, AcceptWithResponder assumes ownership of
   // |responder| and will delete it after calling |responder->Accept| or upon
   // its own destruction.
   //
+  // TODO(yzshen): consider changing |responder| to scoped_ptr<MessageReceiver>.
   virtual bool AcceptWithResponder(Message* message, MessageReceiver* responder)
       MOJO_WARN_UNUSED_RESULT = 0;
 };
 
 // A MessageReceiver that is also able to provide status about the state
 // of the underlying MessagePipe to which it will be forwarding messages
 // received via the |Accept()| call.
 class MessageReceiverWithStatus : public MessageReceiver {
  public:
   ~MessageReceiverWithStatus() override {}
@@ skipping 12 matching lines @@
 
   // A variant on Accept that registers a MessageReceiverWithStatus (known as
   // the responder) to handle the response message generated from the given
   // message. Any of the responder's methods (Accept or IsValid) may be called
   // during  AcceptWithResponder or some time after its return.
   //
   // NOTE: Upon returning true, AcceptWithResponder assumes ownership of
   // |responder| and will delete it after calling |responder->Accept| or upon
   // its own destruction.
   //
+  // TODO(yzshen): consider changing |responder| to scoped_ptr<MessageReceiver>.
   virtual bool AcceptWithResponder(Message* message,
                                    MessageReceiverWithStatus* responder)
       MOJO_WARN_UNUSED_RESULT = 0;
 };
 
 // Read a single message from the pipe. The caller should have created the
 // Message, but not called Initialize(). Returns MOJO_RESULT_SHOULD_WAIT if
 // the caller should wait on the handle to become readable. Returns
 // MOJO_RESULT_OK if the message was read successfully and should be
 // dispatched, otherwise returns an error code if something went wrong.
 //
 // NOTE: The message hasn't been validated and may be malformed!
 MojoResult ReadMessage(MessagePipeHandle handle, Message* message);
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_H_