Clip Scrollbar painting like contents painting in ScrollView

Source/platform/scroll/ScrollView.cpp

 /*
  * Copyright (C) 2006, 2007, 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 875 matching lines @@
     calculateAndPaintOverhangAreas(context, rect);
 
     // Now paint the scrollbars.
     if (!m_scrollbarsSuppressed && (m_horizontalScrollbar || m_verticalScrollbar)) {
         GraphicsContextStateSaver stateSaver(*context);
         IntRect scrollViewDirtyRect = rect;
         IntRect visibleAreaWithScrollbars(location(), visibleContentRect(IncludeScrollbars).size());
         scrollViewDirtyRect.intersect(visibleAreaWithScrollbars);
         context->translate(x(), y());
         scrollViewDirtyRect.moveBy(-location());
+        context->clip(IntRect(IntPoint(), visibleAreaWithScrollbars.size()));
 
         paintScrollbars(context, scrollViewDirtyRect);
     }
 
     // Paint the panScroll Icon
     if (m_drawPanScrollIcon)
         paintPanScrollIcon(context);
 }
 
 void ScrollView::calculateOverhangAreasForPainting(IntRect& horizontalOverhangRect, IntRect& verticalOverhangRect)
@@ skipping 207 matching lines @@
         return;
 
     ScrollableArea::setScrollOrigin(origin);
 
     // Update if the scroll origin changes, since our position will be different if the content size did not change.
     if (updatePositionAtAll && updatePositionSynchronously)
         updateScrollbars(scrollOffset());
 }
 
 } // namespace WebCore