Make RenderObject::style() return a const object

Source/core/html/HTMLSelectElement.h

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google 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
@@ skipping 134 matching lines @@
     virtual bool isInteractiveContent() const override;
     virtual bool supportsAutofocus() const override;
     virtual bool supportLabels() const override { return true; }
 
     virtual FormControlState saveFormControlState() const override;
     virtual void restoreFormControlState(const FormControlState&) override;
 
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) override;
     virtual bool isPresentationAttribute(const QualifiedName&) const override;
 
-    virtual RenderObject* createRenderer(RenderStyle*) override;
+    virtual RenderObject* createRenderer(const RenderStyle*) override;
     virtual bool appendFormData(FormDataList&, bool) override;
     virtual void didAddUserAgentShadowRoot(ShadowRoot&) override;
 
     virtual void defaultEventHandler(Event*) override;
 
     void dispatchInputAndChangeEventForMenuList(bool requiresUserGesture = true);
 
     void recalcListItems(bool updateSelectedStates = true) const;
 
     void typeAheadFind(KeyboardEvent*);
@@ skipping 62 matching lines @@
     bool m_multiple;
     bool m_activeSelectionState;
     mutable bool m_shouldRecalcListItems;
     int m_suggestedIndex;
     bool m_isAutofilledByPreview;
 };
 
 } // namespace blink
 
 #endif // HTMLSelectElement_h