Clean up forward declarations in Source/core/loader

Source/core/loader/PingLoader.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 26 matching lines @@
 #include "platform/Timer.h"
 #include "public/platform/WebURLLoaderClient.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class FormData;
 class LocalFrame;
 class KURL;
-class ResourceError;
-class ResourceHandle;
 class ResourceRequest;
-class ResourceResponse;
 
 // Issue an asynchronous, one-directional request at some resources, ignoring
 // any response. The request is made independent of any LocalFrame staying alive,
 // and must only stay alive until the transmission has completed successfully
 // (or not -- errors are not propagated back either.) Upon transmission, the
 // the load is cancelled and the loader cancels itself.
 //
 // The ping loader is used by audit pings, beacon transmissions and image loads
 // during page unloading.
 //
@@ skipping 27 matching lines @@
 
     OwnPtr<blink::WebURLLoader> m_loader;
     Timer<PingLoader> m_timeout;
     String m_url;
     unsigned long m_identifier;
 };
 
 }
 
 #endif // PingLoader_h