Fix invalidation during painting of scrollbars

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 45 matching lines @@
     virtual int x() const override { return Widget::x(); }
     virtual int y() const override { return Widget::y(); }
     virtual int width() const override { return Widget::width(); }
     virtual int height() const override { return Widget::height(); }
     virtual IntSize size() const override { return Widget::size(); }
     virtual IntPoint location() const override { return Widget::location(); }
 
     virtual Widget* parent() const override { return Widget::parent(); }
     virtual Widget* root() const override { return Widget::root(); }
 
-    virtual void setFrameRect(const IntRect& frameRect) override { Widget::setFrameRect(frameRect); }
+    virtual void setFrameRect(const IntRect&) override;
     virtual IntRect frameRect() const override { return Widget::frameRect(); }
 
     virtual void invalidate() override { Widget::invalidate(); }
     virtual void invalidateRect(const IntRect&) override;
 
     virtual ScrollbarOverlayStyle scrollbarOverlayStyle() const override;
     virtual void getTickmarks(Vector<IntRect>&) const override;
     virtual bool isScrollableAreaActive() const override;
 
     virtual IntPoint convertFromContainingWindow(const IntPoint& windowPoint) override { return Widget::convertFromContainingWindow(windowPoint); }
@@ skipping 128 matching lines @@
     virtual bool isScrollbar() const override { return true; }
 
     float scrollableAreaCurrentPos() const;
 };
 
 DEFINE_TYPE_CASTS(Scrollbar, Widget, widget, widget->isScrollbar(), widget.isScrollbar());
 
 } // namespace blink
 
 #endif // Scrollbar_h