https://bugs.webkit.org/show_bug.cgi?id=123906

Reviewed by Ryosuke Niwa.
        
More code sharing.

* bindings/js/JSDOMWindowCustom.cpp:
(WebCore::namedItemGetter):
* bindings/js/JSHTMLDocumentCustom.cpp:
(WebCore::JSHTMLDocument::nameGetter):
* dom/ChildNodeList.h:
* dom/CollectionIndexCache.h:
(WebCore::::nodeBeforeCached):
(WebCore::::nodeAfterCached):
(WebCore::::nodeAt):
            
    Add a mechanism for disabling use of backward traversal.

* dom/LiveNodeList.h:
(WebCore::LiveNodeList::collectionCanTraverseBackward):
* html/HTMLCollection.cpp:
(WebCore::HTMLCollection::HTMLCollection):
(WebCore::isMatchingElement):
(WebCore::HTMLCollection::iterateForPreviousElement):
(WebCore::firstMatchingElement):
(WebCore::nextMatchingElement):
(WebCore::HTMLCollection::length):
(WebCore::HTMLCollection::item):
(WebCore::nameShouldBeVisibleInDocumentAll):
(WebCore::firstMatchingChildElement):
(WebCore::nextMatchingSiblingElement):
(WebCore::HTMLCollection::firstElement):
(WebCore::HTMLCollection::traverseForward):
(WebCore::HTMLCollection::collectionFirst):
(WebCore::HTMLCollection::collectionLast):
(WebCore::HTMLCollection::collectionTraverseForward):
(WebCore::HTMLCollection::collectionTraverseBackward):
(WebCore::HTMLCollection::invalidateCache):
(WebCore::HTMLCollection::namedItem):
(WebCore::HTMLCollection::updateNameCache):
* html/HTMLCollection.h:
(WebCore::HTMLCollection::collectionCanTraverseBackward):
        
    Disable use of backward traversal for collections that use custom traversal.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@158774 268f45cc-cd09-0410-ab3c-d52691b4dbfc