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

Source/core/html/HTMLInputElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
@@ skipping 1457 matching lines @@
     removeFromRadioButtonGroup();
     HTMLTextFormControlElement::willChangeForm();
 }
 
 void HTMLInputElement::didChangeForm()
 {
     HTMLTextFormControlElement::didChangeForm();
     addToRadioButtonGroup();
 }
 
+void HTMLInputElement::addToRadioButtonGroupCallback(Node* node)
+{
+    ASSERT(node && node->toInputElement());
+    HTMLInputElement* inputElement = node->toInputElement();
+    inputElement->addToRadioButtonGroup();
+}
+
 Node::InsertionNotificationRequest HTMLInputElement::insertedInto(ContainerNode* insertionPoint)
 {
     HTMLTextFormControlElement::insertedInto(insertionPoint);
-    if (insertionPoint->inDocument() && !form())
-        addToRadioButtonGroup();
+    if (insertionPoint->inDocument() && !form() && checkedRadioButtons())
+        queueInsertionCallback(addToRadioButtonGroupCallback, this);
     resetListAttributeTargetObserver();
     return InsertionDone;
 }
 
 void HTMLInputElement::removedFrom(ContainerNode* insertionPoint)
 {
     if (insertionPoint->inDocument() && !form())
         removeFromRadioButtonGroup();
     HTMLTextFormControlElement::removedFrom(insertionPoint);
     ASSERT(!inDocument());
@@ skipping 430 matching lines @@
 }
 
 #if ENABLE(INPUT_MULTIPLE_FIELDS_UI)
 PassRefPtr<RenderStyle> HTMLInputElement::customStyleForRenderer()
 {
     return m_inputType->customStyleForRenderer(originalStyleForRenderer());
 }
 #endif
 
 } // namespace