Make RenderObject::style() return a const object

Source/core/layout/style/LayoutStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 313 matching lines @@
     m_cachedPseudoStyles->append(pseudo);
 
     return result;
 }
 
 void LayoutStyle::removeCachedPseudoStyle(PseudoId pid)
 {
     if (!m_cachedPseudoStyles)
         return;
     for (size_t i = 0; i < m_cachedPseudoStyles->size(); ++i) {
-        LayoutStyle* pseudoStyle = m_cachedPseudoStyles->at(i).get();
-        if (pseudoStyle->styleType() == pid) {
+        const LayoutStyle& pseudoStyle = *m_cachedPseudoStyles->at(i);
+        if (pseudoStyle.styleType() == pid) {
             m_cachedPseudoStyles->remove(i);
             return;
         }
     }
 }
 
 bool LayoutStyle::inheritedNotEqual(const LayoutStyle& other) const
 {
     return inherited_flags != other.inherited_flags
         || inherited != other.inherited
@@ skipping 1319 matching lines @@
         horizontal || includeLogicalRightEdge);
 
     edges[BSLeft] = BorderEdge(borderLeftWidth(),
         visitedDependentColor(CSSPropertyBorderLeftColor),
         borderLeftStyle(),
         borderLeftIsTransparent(),
         !horizontal || includeLogicalLeftEdge);
 }
 
 } // namespace blink