Clean up forward declarations in Source/platform

Source/platform/scroll/ScrollAnimatorNone.h

 /*
  * Copyright (c) 2011, 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 21 matching lines @@
 #define ScrollAnimatorNone_h
 
 #include "platform/Timer.h"
 #include "platform/geometry/FloatPoint.h"
 #include "platform/scroll/ScrollAnimator.h"
 
 class ScrollAnimatorNoneTest;
 
 namespace blink {
 
-class IntPoint;
-class ActivePlatformGestureAnimation;
-struct ScrollAnimatorParameters;
-
 class PLATFORM_EXPORT ScrollAnimatorNone : public ScrollAnimator {
 public:
     explicit ScrollAnimatorNone(ScrollableArea*);
     virtual ~ScrollAnimatorNone();
 
     virtual bool scroll(ScrollbarOrientation, ScrollGranularity, float step, float delta) OVERRIDE;
     virtual void scrollToOffsetWithoutAnimation(const FloatPoint&) OVERRIDE;
 
     virtual void cancelAnimations() OVERRIDE;
     virtual void serviceScrollAnimations() OVERRIDE;
@@ skipping 91 matching lines @@
     PerAxisData m_horizontalData;
     PerAxisData m_verticalData;
 
     double m_startTime;
     bool m_animationActive;
 };
 
 } // namespace blink
 
 #endif // ScrollAnimatorNone_h