select.add() should support optgroup adding and before index

Source/core/html/HTMLSelectElement.cpp

 /*
  * 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) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
@@ skipping 185 matching lines @@
     if (m_activeSelectionEndIndex >= 0)
         return m_activeSelectionEndIndex;
     return lastSelectedListIndex();
 }
 
 void HTMLSelectElement::add(HTMLElement* element, HTMLElement* before, ExceptionState& exceptionState)
 {
     // Make sure the element is ref'd and deref'd so we don't leak it.
     RefPtr<HTMLElement> protectNewChild(element);
 
-    if (!element || !(isHTMLOptionElement(element) || isHTMLHRElement(element)))
+    if (!element || !(isHTMLOptionElement(element) || isHTMLOptGroupElement(element) || isHTMLHRElement(element)))
         return;
 
     insertBefore(element, before, exceptionState);
     setNeedsValidityCheck();
 }
 
+void HTMLSelectElement::addBeforeOptionAtIndex(HTMLElement* element, unsigned beforeIndex, ExceptionState& exceptionState)
+{
+    HTMLElement* beforeElement = toHTMLElement(options()->item(beforeIndex));
+    add(element, beforeElement, exceptionState);
+}
+
 void HTMLSelectElement::remove(int optionIndex)
 {
     int listIndex = optionToListIndex(optionIndex);
     if (listIndex < 0)
         return;
 
     listItems()[listIndex]->remove(IGNORE_EXCEPTION);
 }
 
 String HTMLSelectElement::value() const
@@ skipping 1394 matching lines @@
 {
     return true;
 }
 
 bool HTMLSelectElement::supportsAutofocus() const
 {
     return true;
 }
 
 } // namespace