Make RenderObject::style() return a const object

Source/core/rendering/RenderFrameSet.cpp

 /**
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  *           (C) 2000 Stefan Schimanski (1Stein@gmx.de)
  * Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 541 matching lines @@
 
     int splitPosition = axis.m_sizes[0];
     for (size_t i = 1; i < size; ++i) {
         if (position >= splitPosition && position < splitPosition + borderThickness)
             return i;
         splitPosition += borderThickness + axis.m_sizes[i];
     }
     return noSplit;
 }
 
-bool RenderFrameSet::isChildAllowed(RenderObject* child, RenderStyle*) const
+bool RenderFrameSet::isChildAllowed(RenderObject* child, const RenderStyle*) const
 {
     return child->isFrame() || child->isFrameSet();
 }
 
 CursorDirective RenderFrameSet::getCursor(const LayoutPoint& point, Cursor& cursor) const
 {
     IntPoint roundedPoint = roundedIntPoint(point);
     if (canResizeRow(roundedPoint)) {
         cursor = rowResizeCursor();
         return SetCursor;
     }
     if (canResizeColumn(roundedPoint)) {
         cursor = columnResizeCursor();
         return SetCursor;
     }
     return RenderBox::getCursor(point, cursor);
 }
 
 } // namespace blink