Cleanup remaining class/struct fwd declarations

mojo/edk/system/shared_buffer_dispatcher.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_EDK_SYSTEM_SHARED_BUFFER_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_SHARED_BUFFER_DISPATCHER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
 
 #include "base/macros.h"
 #include "mojo/edk/embedder/platform_handle_vector.h"
 #include "mojo/edk/embedder/platform_shared_buffer.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/edk/system/dispatcher.h"
 #include "mojo/edk/system/system_impl_export.h"
 
 namespace mojo {
 
 namespace edk {
 class NodeController;
-class PlatformSupport;
 
 class MOJO_SYSTEM_IMPL_EXPORT SharedBufferDispatcher final : public Dispatcher {
  public:
   // The default options to use for |MojoCreateSharedBuffer()|. (Real uses
   // should obtain this via |ValidateCreateOptions()| with a null |in_options|;
   // this is exposed directly for testing convenience.)
   static const MojoCreateSharedBufferOptions kDefaultCreateOptions;
 
   // Validates and/or sets default options for |MojoCreateSharedBufferOptions|.
   // If non-null, |in_options| must point to a struct of at least
@@ skipping 84 matching lines @@
 
   scoped_refptr<PlatformSharedBuffer> shared_buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedBufferDispatcher);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_SHARED_BUFFER_DISPATCHER_H_