blimp: Cleanup class/struct forward declarations

blimp/net/blimp_message_thread_pipe.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 BLIMP_NET_BLIMP_MESSAGE_THREAD_PIPE_H_
 #define BLIMP_NET_BLIMP_MESSAGE_THREAD_PIPE_H_
 
 #include <memory>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "blimp/net/blimp_net_export.h"
 
 namespace base {
 class SequencedTaskRunner;
 }
 
 namespace blimp {
 
-class BlimpMessage;
 class BlimpMessageProcessor;
 
 // Uni-directional MessageProcessor "pipe" that accepts messages on
 // one thread and dispatches them to a MessageProcessor on a different
 // thread.
 //
 // Typical usage involves:
 // 1. Create the pipe on the "main" thread, specifying the target thread's
 //    task runner.
 // 2. Take one or more MessageProcessor proxies from it.
@@ skipping 28 matching lines @@
 
   // Allows |this| to be safely detached from existing proxies on deletion.
   base::WeakPtrFactory<BlimpMessageThreadPipe> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BlimpMessageThreadPipe);
 };
 
 }  // namespace blimp
 
 #endif  // BLIMP_NET_BLIMP_MESSAGE_THREAD_PIPE_H_