Clean up forward declarations in Source/platform

Source/platform/HostWindow.h

 /*
  * Copyright (C) 2008 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 13 matching lines @@
  */
 
 #ifndef HostWindow_h
 #define HostWindow_h
 
 #include "platform/PlatformExport.h"
 #include "wtf/FastAllocBase.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
-class Cursor;
-class IntPoint;
 class IntRect;
-class IntSize;
 struct WebScreenInfo;
 
 class PLATFORM_EXPORT HostWindow {
     WTF_MAKE_NONCOPYABLE(HostWindow); WTF_MAKE_FAST_ALLOCATED;
 public:
     HostWindow() { }
     virtual ~HostWindow() { }
 
     // Requests the host invalidate the contents and the root view.
     virtual void invalidateContentsAndRootView(const IntRect& updateRect) = 0;
 
     // Requests the host invalidate the contents, not the root view. This is the slow path for scrolling.
     virtual void invalidateContentsForSlowScroll(const IntRect& updateRect) = 0;
 
     // Methods for doing coordinate conversions to screen coordinates.
     virtual IntRect rootViewToScreen(const IntRect&) const = 0;
 
     virtual WebScreenInfo screenInfo() const = 0;
 
     virtual void scheduleAnimation() = 0;
 };
 
 } // namespace blink
 
 #endif // HostWindow_h