Remove unused InvalidateOnItemAttrChange NodeList invalidation type

Source/core/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 173 matching lines @@
 };
 
 enum NodeListInvalidationType {
     DoNotInvalidateOnAttributeChanges = 0,
     InvalidateOnClassAttrChange,
     InvalidateOnIdNameAttrChange,
     InvalidateOnNameAttrChange,
     InvalidateOnForAttrChange,
     InvalidateForFormControls,
     InvalidateOnHRefAttrChange,
-    InvalidateOnItemAttrChange,
     InvalidateOnAnyAttrChange,
 };
 const int numNodeListInvalidationTypes = InvalidateOnAnyAttrChange + 1;
 
 typedef HashCountedSet<Node*> TouchEventTargetSet;
 
 enum DocumentClass {
     DefaultDocumentClass = 0,
     HTMLDocumentClass = 1,
     XHTMLDocumentClass = 1 << 1,
@@ skipping 1186 matching lines @@
 inline bool Node::isDocumentNode() const
 {
     return this == document();
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h