Make RenderObject::style() return a const object

Source/core/html/HTMLPlugInElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2012 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 107 matching lines @@
 
     // Node functions:
     virtual bool canContainRangeEndPoint() const override { return false; }
     virtual bool willRespondToMouseClickEvents() override final;
     virtual void defaultEventHandler(Event*) override final;
     virtual void attach(const AttachContext& = AttachContext()) override final;
     virtual void detach(const AttachContext& = AttachContext()) override final;
     virtual void finishParsingChildren() override final;
 
     // Element functions:
-    virtual RenderObject* createRenderer(RenderStyle*) override;
+    virtual RenderObject* createRenderer(const RenderStyle*) override;
     virtual bool supportsFocus() const override final { return true; }
     virtual bool rendererIsFocusable() const override final;
     virtual bool isKeyboardFocusable() const override final;
     virtual void didAddUserAgentShadowRoot(ShadowRoot&) override final;
     virtual void willAddFirstAuthorShadowRoot() override final;
 
     // HTMLElement function:
     virtual bool hasCustomFocusLogic() const override;
     virtual bool isPluginElement() const override final;
 
@@ skipping 27 matching lines @@
 inline bool isHTMLPlugInElement(const HTMLElement& element)
 {
     return element.isPluginElement();
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLPlugInElement);
 
 } // namespace blink
 
 #endif // HTMLPlugInElement_h