Clean up forward declarations in Source/core/page

Source/core/page/DragController.h

 /*
  * Copyright (C) 2007, 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
 
 namespace blink {
 
 class DataTransfer;
 class Document;
 class DragClient;
 class DragData;
 class DragImage;
 struct DragSession;
 class DragState;
-class Element;
 class LocalFrame;
 class FrameSelection;
 class HTMLInputElement;
-class Image;
-class IntRect;
 class Node;
 class Page;
 class PlatformMouseEvent;
-class Range;
 
 class DragController FINAL : public NoBaseWillBeGarbageCollectedFinalized<DragController> {
     WTF_MAKE_NONCOPYABLE(DragController);
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
 public:
     ~DragController();
 
     static PassOwnPtrWillBeRawPtr<DragController> create(Page*, DragClient*);
 
     DragSession dragEntered(DragData*);
@@ skipping 44 matching lines @@
     RefPtrWillBeMember<HTMLInputElement> m_fileInputElementUnderMouse;
     bool m_documentIsHandlingDrag;
 
     DragDestinationAction m_dragDestinationAction;
     bool m_didInitiateDrag;
 };
 
 } // namespace blink
 
 #endif // DragController_h