Add number() static methods to AtomicString class

Source/core/html/HTMLOListElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2010 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 77 matching lines @@
         if (reversed == m_isReversed)
             return;
         m_isReversed = reversed;
         updateItemValues();
     } else
         HTMLElement::parseAttribute(name, value);
 }
 
 void HTMLOListElement::setStart(int start)
 {
-    setAttribute(startAttr, String::number(start));
+    setIntegralAttribute(startAttr, start);
 }
 
 void HTMLOListElement::updateItemValues()
 {
     RenderListItem::updateItemValuesForOrderedList(this);
 }
 
 void HTMLOListElement::recalculateItemCount()
 {
     m_itemCount = RenderListItem::itemCountForOrderedList(this);
     m_shouldRecalculateItemCount = false;
 }
 
 }