Make RenderObject::style() return a const object

Source/core/rendering/RenderFrameSet.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 2006, 2008 Apple Inc. 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 90 matching lines @@
 
     virtual RenderObjectChildList* virtualChildren() override { return children(); }
     virtual const RenderObjectChildList* virtualChildren() const override { return children(); }
 
     virtual const char* renderName() const override { return "RenderFrameSet"; }
     virtual bool isOfType(RenderObjectType type) const override { return type == RenderObjectFrameSet || RenderBox::isOfType(type); }
 
     virtual void layout() override;
     virtual void paint(const PaintInfo&, const LayoutPoint&) override;
     virtual void computePreferredLogicalWidths() override;
-    virtual bool isChildAllowed(RenderObject*, RenderStyle*) const override;
+    virtual bool isChildAllowed(RenderObject*, const RenderStyle*) const override;
     virtual CursorDirective getCursor(const LayoutPoint&, Cursor&) const override;
 
     void setIsResizing(bool);
 
     void layOutAxis(GridAxis&, const Vector<HTMLDimension>&, int availableSpace);
     void computeEdgeInfo();
     void fillFromEdgeInfo(const FrameEdgeInfo& edgeInfo, int r, int c);
     void positionFrames();
 
     int splitPosition(const GridAxis&, int split) const;
     int hitTestSplit(const GridAxis&, int position) const;
 
     void startResizing(GridAxis&, int position);
     void continueResizing(GridAxis&, int position);
 
     RenderObjectChildList m_children;
 
     GridAxis m_rows;
     GridAxis m_cols;
 
     bool m_isResizing;
     bool m_isChildResizing;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderFrameSet, isFrameSet());
 
 } // namespace blink
 
 #endif // RenderFrameSet_h