WebKit merge 40668:40722 part 1.

third_party/WebKit/WebCore/rendering/RenderButton.h

 /*
  * This file is part of the html renderer for KDE.
  *
  * Copyright (C) 2005 Apple Computer
  *
  * 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 21 matching lines @@
 class RenderTextFragment;
 
 // RenderButtons are just like normal flexboxes except that they will generate an anonymous block child.
 // For inputs, they will also generate an anonymous RenderText and keep its style and content up
 // to date as the button changes.
 class RenderButton : public RenderFlexibleBox {
 public:
     RenderButton(Node*);
 
     virtual const char* renderName() const { return "RenderButton"; }
+    virtual bool isRenderButton() const { return true; }
 
     virtual void addChild(RenderObject* newChild, RenderObject *beforeChild = 0);
     virtual void removeChild(RenderObject*);
     virtual void removeLeftoverAnonymousBlock(RenderBlock*) { }
     virtual bool createsAnonymousWrapper() const { return true; }
 
     void setupInnerStyle(RenderStyle*);
     virtual void updateFromElement();
 
     virtual void updateBeforeAfterContent(PseudoId);
@@ skipping 13 matching lines @@
 
     void timerFired(Timer<RenderButton>*);
 
     RenderTextFragment* m_buttonText;
     RenderBlock* m_inner;
 
     OwnPtr<Timer<RenderButton> > m_timer;
     bool m_default;
 };
 
+inline RenderButton* toRenderButton(RenderObject* o)
+{ 
+    ASSERT(!o || o->isRenderButton());
+    return static_cast<RenderButton*>(o);
+}
+
+inline const RenderButton* toRenderButton(const RenderObject* o)
+{ 
+    ASSERT(!o || o->isRenderButton());
+    return static_cast<const RenderButton*>(o);
+}
+
+// This will catch anyone doing an unnecessary cast.
+void toRenderButton(const RenderButton*);
+
 } // namespace WebCore
 
 #endif // RenderButton_h