Do not re-register cached id-name HTMLCollection at same invalidation type

third_party/WebKit/Source/core/html/HTMLCollection.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. 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 99 matching lines @@
     virtual Element* virtualItemAfter(Element*) const;
     bool shouldOnlyIncludeDirectChildren() const { return m_shouldOnlyIncludeDirectChildren; }
     virtual void supportedPropertyNames(Vector<String>& names);
 
     virtual void updateIdNameCache() const;
     bool hasValidIdNameCache() const { return m_namedItemCache; }
 
     void setNamedItemCache(PassOwnPtrWillBeRawPtr<NamedItemCache> cache) const
     {
         ASSERT(!m_namedItemCache);
-        document().registerNodeListWithIdNameCache(this);
+        // Do not repeat registration for the same invalidation type.
+        if (invalidationType() != InvalidateOnIdNameAttrChange)
+            document().registerNodeListWithIdNameCache(this);
         m_namedItemCache = std::move(cache);
     }
 
     NamedItemCache& namedItemCache() const
     {
         ASSERT(m_namedItemCache);
         return *m_namedItemCache;
     }
 
 private:
     void invalidateIdNameCacheMaps(Document* oldDocument = 0) const
     {
         if (!hasValidIdNameCache())
             return;
 
         // Make sure we decrement the NodeListWithIdNameCache count from
         // the old document instead of the new one in the case the collection
         // is moved to a new document.
         unregisterIdNameCacheFromDocument(oldDocument ? *oldDocument : document());
 
         m_namedItemCache.clear();
     }
 
     void unregisterIdNameCacheFromDocument(Document& document) const
     {
         ASSERT(hasValidIdNameCache());
-        document.unregisterNodeListWithIdNameCache(this);
+        // Do not repeat unregistration for the same invalidation type.
+        if (invalidationType() != InvalidateOnIdNameAttrChange)
+            document.unregisterNodeListWithIdNameCache(this);
     }
 
     const unsigned m_overridesItemAfter : 1;
     const unsigned m_shouldOnlyIncludeDirectChildren : 1;
     mutable OwnPtrWillBeMember<NamedItemCache> m_namedItemCache;
     mutable CollectionItemsCache<HTMLCollection, Element> m_collectionItemsCache;
 };
 
 DEFINE_TYPE_CASTS(HTMLCollection, LiveNodeListBase, collection, isHTMLCollectionType(collection->type()), isHTMLCollectionType(collection.type()));
 
 inline void HTMLCollection::invalidateCacheForAttribute(const QualifiedName* attrName) const
 {
     if (!attrName || shouldInvalidateTypeOnAttributeChange(invalidationType(), *attrName))
         invalidateCache();
     else if (*attrName == HTMLNames::idAttr || *attrName == HTMLNames::nameAttr)
         invalidateIdNameCacheMaps();
 }
 
 } // namespace blink
 
 #endif // HTMLCollection_h