Make RenderObject::style() return a const object

Source/core/rendering/RenderMultiColumnFlowThread.cpp

 /*
  * 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 29 matching lines @@
     , m_progressionIsInline(true)
     , m_isBeingEvacuated(false)
 {
     setFlowThreadState(InsideInFlowThread);
 }
 
 RenderMultiColumnFlowThread::~RenderMultiColumnFlowThread()
 {
 }
 
-RenderMultiColumnFlowThread* RenderMultiColumnFlowThread::createAnonymous(Document& document, RenderStyle* parentStyle)
+RenderMultiColumnFlowThread* RenderMultiColumnFlowThread::createAnonymous(Document& document, const RenderStyle* parentStyle)
 {
     RenderMultiColumnFlowThread* renderer = new RenderMultiColumnFlowThread();
     renderer->setDocumentForAnonymous(&document);
     renderer->setStyle(RenderStyle::createAnonymousStyleWithDisplay(parentStyle, BLOCK));
     return renderer;
 }
 
 RenderMultiColumnSet* RenderMultiColumnFlowThread::firstMultiColumnSet() const
 {
     for (RenderObject* sibling = nextSibling(); sibling; sibling = sibling->nextSibling()) {
@@ skipping 607 matching lines @@
 }
 
 bool RenderMultiColumnFlowThread::isPageLogicalHeightKnown() const
 {
     if (RenderMultiColumnSet* columnSet = lastMultiColumnSet())
         return columnSet->pageLogicalHeight();
     return false;
 }
 
 }