Clean up BoxClipper

Source/core/layout/LayoutBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 1378 matching lines @@
 bool LayoutBox::paintInvalidationStateIsDirty() const
 {
     if (ScrollableArea* area = scrollableArea()) {
         if (area->hasVerticalBarDamage() || area->hasHorizontalBarDamage())
             return true;
     }
     return LayoutBoxModelObject::paintInvalidationStateIsDirty();
 }
 #endif
 
-LayoutRect LayoutBox::overflowClipRect(const LayoutPoint& location, OverlayScrollbarSizeRelevancy relevancy)
+LayoutRect LayoutBox::overflowClipRect(const LayoutPoint& location, OverlayScrollbarSizeRelevancy relevancy) const
 {
     // FIXME: When overflow-clip (CSS3) is implemented, we'll obtain the property
     // here.
     LayoutRect clipRect = borderBoxRect();
     clipRect.setLocation(location + clipRect.location() + LayoutSize(borderLeft(), borderTop()));
     clipRect.setSize(clipRect.size() - LayoutSize(borderLeft() + borderRight(), borderTop() + borderBottom()));
 
     if (!hasOverflowClip())
         return clipRect;
 
@@ skipping 3338 matching lines @@
 bool LayoutBox::canRenderBorderImage() const
 {
     if (!style()->hasBorderDecoration())
         return false;
 
     StyleImage* borderImage = style()->borderImage().image();
     return borderImage && borderImage->canRender(*this, style()->effectiveZoom()) && borderImage->isLoaded();
 }
 
 } // namespace blink