content: Cleanup class/struct forward declarations

content/browser/loader/navigation_url_loader_impl_core.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 CONTENT_BROWSER_LOADER_NAVIGATION_URL_LOADER_IMPL_CORE_H_
 #define CONTENT_BROWSER_LOADER_NAVIGATION_URL_LOADER_IMPL_CORE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "content/browser/loader/navigation_url_loader_impl.h"
 
 namespace net {
-class URLRequest;
 struct RedirectInfo;
 }
 
 namespace content {
 
-class FrameTreeNode;
 class NavigationResourceHandler;
 class NavigationData;
 class ResourceContext;
 class ResourceHandler;
-class ResourceRequestBody;
 class ServiceWorkerNavigationHandleCore;
 class StreamHandle;
 struct ResourceResponse;
 struct SSLStatus;
 
 // The IO-thread counterpart to the NavigationURLLoaderImpl. It lives on the IO
 // thread and is owned by the UI-thread NavigationURLLoaderImpl.
 // NavigationURLLoaderImplCore interacts with the ResourceDispatcherHost stack
 // and forwards signals back to the loader on the UI thread.
 class NavigationURLLoaderImplCore {
@@ skipping 36 matching lines @@
  private:
   base::WeakPtr<NavigationURLLoaderImpl> loader_;
   NavigationResourceHandler* resource_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationURLLoaderImplCore);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_LOADER_NAVIGATION_URL_LOADER_IMPL_CORE_H_