Avoid N^2 walk placing renderers when building the render tree

Source/core/html/HTMLInputElement.h

 /*
  * 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, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Samsung Electronics. 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
@@ skipping 289 matching lines @@
     enum AutoCompleteSetting { Uninitialized, On, Off };
 
     // FIXME: Author shadows should be allowed
     // https://bugs.webkit.org/show_bug.cgi?id=92608
     virtual bool areAuthorShadowsAllowed() const OVERRIDE { return false; }
 
     virtual void didAddUserAgentShadowRoot(ShadowRoot*) OVERRIDE;
 
     virtual void willChangeForm() OVERRIDE;
     virtual void didChangeForm() OVERRIDE;
+    static void addToRadioButtonGroupCallback(Element*);
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
     virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual void didMoveToNewDocument(Document* oldDocument) OVERRIDE;
 
     virtual bool hasCustomFocusLogic() const OVERRIDE;
     virtual bool isKeyboardFocusable(KeyboardEvent*) const;
     virtual bool shouldShowFocusRingOnMouseFocus() const OVERRIDE;
     virtual bool isEnumeratable() const;
     virtual bool supportLabels() const OVERRIDE;
     virtual void updateFocusAppearance(bool restorePreviousSelection);
@@ skipping 110 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(HTMLNames::inputTag));
     return static_cast<const HTMLInputElement*>(node);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toHTMLElement(const HTMLElement*);
 
 
 } //namespace
 #endif