LiveNodeListBase code should not need to worry about id/name cache invalidation

Source/core/html/HTMLCollection.h

Index: Source/core/html/HTMLCollection.h
diff --git a/Source/core/html/HTMLCollection.h b/Source/core/html/HTMLCollection.h
index 16b57382f8e5be98a31994a0ccd104b91dfb8436..4f6d52a467a501c0402f0784c8d0a8aa38677569 100644
--- a/Source/core/html/HTMLCollection.h
+++ b/Source/core/html/HTMLCollection.h
@@ -43,6 +43,7 @@ public:
     static PassRefPtr<HTMLCollection> create(ContainerNode& base, CollectionType);
     virtual ~HTMLCollection();
     virtual void invalidateCache(Document* oldDocument = 0) const OVERRIDE;
+    void invalidateCacheForAttribute(const QualifiedName*) const;
 
     // DOM API
     unsigned length() const { return m_collectionIndexCache.nodeCount(*this); }
@@ -140,10 +141,18 @@ private:
     const unsigned m_shouldOnlyIncludeDirectChildren : 1;
     mutable OwnPtr<NamedItemCache> m_namedItemCache;
     mutable CollectionIndexCache<HTMLCollection, Element> m_collectionIndexCache;
-
-    friend class LiveNodeListBase;
 };
 
+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
 
 #endif