Moving GraphicsContext and dependencies from core to platform.

Source/platform/scroll/Scrollbar.h

 /*
  * Copyright (C) 2004, 2006 Apple Computer, 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 25 matching lines @@
 namespace WebCore {
 
 class GraphicsContext;
 class IntRect;
 class PlatformGestureEvent;
 class PlatformMouseEvent;
 class ScrollableArea;
 class ScrollbarTheme;
 class ScrollView;
 
-class Scrollbar : public Widget,
+class PLATFORM_EXPORT Scrollbar : public Widget,
                   public ScrollbarThemeClient {
 
 public:
     static PassRefPtr<Scrollbar> create(ScrollableArea*, ScrollbarOrientation, ScrollbarControlSize);
 
     virtual ~Scrollbar();
 
     // ScrollbarThemeClient implementation.
     virtual int x() const { return Widget::x(); }
     virtual int y() const { return Widget::y(); }
@@ skipping 150 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!widget || widget->isScrollbar());
     return static_cast<const Scrollbar*>(widget);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toScrollbar(const Scrollbar*);
 
 } // namespace WebCore
 
 #endif // Scrollbar_h