Delete a bunch of noop paint invalidation code.

sky/engine/core/rendering/RenderLayerScrollableArea.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 49 matching lines @@
     virtual ~RenderLayerScrollableArea();
 
     bool hasHorizontalScrollbar() const { return horizontalScrollbar(); }
     bool hasVerticalScrollbar() const { return verticalScrollbar(); }
 
     Scrollbar* horizontalScrollbar() const override { return m_hBar.get(); }
     Scrollbar* verticalScrollbar() const override { return m_vBar.get(); }
 
     HostWindow* hostWindow() const override;
 
-    void invalidateScrollbarRect(Scrollbar*, const IntRect&) override;
     bool isActive() const override;
     IntRect scrollCornerRect() const;
     IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const override;
     IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const override;
     IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const override;
     IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const override;
     int scrollSize(ScrollbarOrientation) const override;
     void setScrollOffset(const IntPoint&) override;
     IntPoint scrollPosition() const override;
     IntPoint minimumScrollPosition() const override;
@@ skipping 107 matching lines @@
     IntPoint m_cachedOverlayScrollbarOffset;
 
     // For areas with overflow, we have a pair of scrollbars.
     RefPtr<Scrollbar> m_hBar;
     RefPtr<Scrollbar> m_vBar;
 };
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_RENDERING_RENDERLAYERSCROLLABLEAREA_H_