[mojo-edk] Add explicit message object APIs

mojo/edk/system/message_pipe_dispatcher.h

 // Copyright 2015 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_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 
 #include <stdint.h>
 
 #include <queue>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "mojo/edk/system/awakable_list.h"
 #include "mojo/edk/system/dispatcher.h"
 #include "mojo/edk/system/ports/port_ref.h"
 
 namespace mojo {
 namespace edk {
 
+class MessageForTransit;
 class NodeController;
 class PortsMessage;
 
 class MessagePipeDispatcher : public Dispatcher {
  public:
   // Constructs a MessagePipeDispatcher permanently tied to a specific port.
   // |connected| must indicate the state of the port at construction time; if
   // the port is initialized with a peer, |connected| must be true. Otherwise it
   // must be false.
   //
@@ skipping 13 matching lines @@
   // this call.
   bool Fuse(MessagePipeDispatcher* other);
 
   // Dispatcher:
   Type GetType() const override;
   MojoResult Close() override;
   MojoResult Watch(MojoHandleSignals signals,
                    const Watcher::WatchCallback& callback,
                    uintptr_t context) override;
   MojoResult CancelWatch(uintptr_t context) override;
-  MojoResult WriteMessage(const void* bytes,
-                          uint32_t num_bytes,
-                          const DispatcherInTransit* dispatchers,
-                          uint32_t num_dispatchers,
+  MojoResult WriteMessage(std::unique_ptr<MessageForTransit> message,
                           MojoWriteMessageFlags flags) override;
-  MojoResult ReadMessage(void* bytes,
+  MojoResult ReadMessage(std::unique_ptr<MessageForTransit>* message,
                          uint32_t* num_bytes,
                          MojoHandle* handles,
                          uint32_t* num_handles,
-                         MojoReadMessageFlags flags) override;
+                         MojoReadMessageFlags flags,
+                         bool ignore_num_bytes) override;
   HandleSignalsState GetHandleSignalsState() const override;
   MojoResult AddAwakable(Awakable* awakable,
                          MojoHandleSignals signals,
                          uintptr_t context,
                          HandleSignalsState* signals_state) override;
   void RemoveAwakable(Awakable* awakable,
                       HandleSignalsState* signals_state) override;
   void StartSerialize(uint32_t* num_bytes,
                       uint32_t* num_ports,
                       uint32_t* num_handles) override;
@@ skipping 39 matching lines @@
   bool port_closed_ = false;
   AwakableList awakables_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePipeDispatcher);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_