Cleanup remaining class/struct fwd declarations

ipc/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 <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "base/atomicops.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/process/process_handle.h"
 #include "base/threading/thread_checker.h"
 #include "ipc/ipc.mojom.h"
 #include "ipc/ipc_export.h"
 #include "ipc/ipc_message.h"
 #include "mojo/public/cpp/bindings/associated_binding.h"
 #include "mojo/public/cpp/bindings/scoped_interface_endpoint_handle.h"
 #include "mojo/public/cpp/system/core.h"
 #include "mojo/public/cpp/system/message_pipe.h"
 
 namespace IPC {
 namespace internal {
 
-class AsyncHandleWaiter;
-
 // 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
 // read the stream and call the client when it is ready.
 //
 // Each client has to:
 //
 //  * Provide a subclass implemenation of a specific use of a MessagePipe
 //    and implement callbacks.
 //  * Create the subclass instance with a MessagePipeHandle.
@@ skipping 67 matching lines @@
   mojo::AssociatedBinding<mojom::Channel> binding_;
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePipeReader);
 };
 
 }  // namespace internal
 }  // namespace IPC
 
 #endif  // IPC_IPC_MESSAGE_PIPE_READER_H_