Make RenderObject::style() return a const object

Source/core/rendering/RenderMultiColumnSet.h

 /*
  * Copyright (C) 2012 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 36 matching lines @@
 // contents, and to paint any rules between them. RenderMultiColumnSet objects are used for
 // painting, hit testing, and any other type of operation that requires mapping from flow thread
 // coordinates to visual coordinates.
 //
 // Column spans result in the creation of new column sets, since a spanning renderer has to be
 // placed in between the column sets that come before and after the span.
 class RenderMultiColumnSet : public RenderRegion {
 public:
     enum BalancedHeightCalculation { GuessFromFlowThreadPortion, StretchBySpaceShortage };
 
-    static RenderMultiColumnSet* createAnonymous(RenderFlowThread*, RenderStyle* parentStyle);
+    static RenderMultiColumnSet* createAnonymous(RenderFlowThread*, const RenderStyle* parentStyle);
 
     virtual bool isOfType(RenderObjectType type) const override { return type == RenderObjectRenderMultiColumnSet || RenderRegion::isOfType(type); }
 
     virtual LayoutUnit pageLogicalWidth() const override final { return flowThread()->logicalWidth(); }
     virtual LayoutUnit pageLogicalHeight() const override final { return m_columnHeight; }
 
     RenderBlockFlow* multiColumnBlockFlow() const { return toRenderBlockFlow(parent()); }
     RenderMultiColumnFlowThread* multiColumnFlowThread() const
     {
         ASSERT_WITH_SECURITY_IMPLICATION(!flowThread() || flowThread()->isRenderMultiColumnFlowThread());
@@ skipping 164 matching lines @@
     // initial margin collapsing estimates were wrong.
     setLogicalBottomInFlowThread(offsetInFlowThread);
 }
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderMultiColumnSet, isRenderMultiColumnSet());
 
 } // namespace blink
 
 #endif // RenderMultiColumnSet_h