Cleanup remaining class/struct fwd declarations

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 <memory>
 #include <queue>
 
 #include "base/macros.h"
 #include "mojo/edk/system/atomic_flag.h"
 #include "mojo/edk/system/awakable_list.h"
 #include "mojo/edk/system/dispatcher.h"
 #include "mojo/edk/system/message_for_transit.h"
 #include "mojo/edk/system/ports/port_ref.h"
 
 namespace mojo {
 namespace edk {
 
 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.
   //
   // A MessagePipeDispatcher may not be transferred while in a disconnected
   // state, and one can never return to a disconnected once connected.
@@ skipping 78 matching lines @@
   AtomicFlag port_closed_;
   AwakableList awakables_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePipeDispatcher);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_