extensions: Cleanup class/struct fwd declarations

extensions/renderer/worker_thread_dispatcher.h

 // Copyright 2016 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 EXTENSIONS_RENDERER_WORKER_THREAD_DISPATCHER_H_
 #define EXTENSIONS_RENDERER_WORKER_THREAD_DISPATCHER_H_
 
 #include "base/synchronization/lock.h"
 #include "content/public/renderer/render_thread_observer.h"
 #include "ipc/ipc_sync_message_filter.h"
 
 namespace base {
 class ListValue;
 }
 
 namespace content {
 class RenderThread;
 }
 
 namespace extensions {
 class ExtensionBindingsSystem;
 class ResourceBundleSourceMap;
-class RequestSender;
 class ServiceWorkerRequestSender;
 class V8SchemaRegistry;
 
 // Sends and receives IPC in an extension Service Worker.
 // TODO(lazyboy): This class should really be a combination of the following
 // two:
 // 1) A content::WorkerThreadMessageFilter, so that we can receive IPC directly
 // on worker thread.
 // 2) A content::ThreadSafeSender, so we can safely send IPC from worker thread.
 class WorkerThreadDispatcher : public content::RenderThreadObserver {
@@ skipping 26 matching lines @@
 
   // IPC sender. Belongs to the render thread, but thread safe.
   scoped_refptr<IPC::SyncMessageFilter> message_filter_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkerThreadDispatcher);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_WORKER_THREAD_DISPATCHER_H_