Add number() static methods to AtomicString class

Source/core/html/HTMLTableColElement.cpp

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 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
@@ skipping 73 matching lines @@
 {
     if (!hasLocalName(colgroupTag))
         return 0;
     if (HTMLTableElement* table = findParentTable())
         return table->additionalGroupStyle(false);
     return 0;
 }
 
 void HTMLTableColElement::setSpan(int n)
 {
-    setAttribute(spanAttr, String::number(n));
+    setIntegralAttribute(spanAttr, n);
 }
 
 String HTMLTableColElement::width() const
 {
     return getAttribute(widthAttr);
 }
 
 }