Drop traverseNextElement() method from HTMLCollection class

Drop traverseNextElement() method from HTMLCollection class to avoid code
duplication with traverseForwardToOffset(). This method was only used
by supportedPropertyNames() and updateIdNameCache(). Now these methods
uses the standard traversal API (HTMLCollection::length() / item(index)),
and thus the standard code path for HTMLCollection traversal.

I did not see any regression with this change on Dromaeo:
http://dromaeo.com/?id=223149,223150

R=adamk@chromium.org, esprehn@chromium.org

Review URL: https://codereview.chromium.org/336133002

git-svn-id: svn://svn.chromium.org/blink/trunk@176253 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -365,15 +365,6 @@ Element* HTMLCollection::traverseToLastElement() const
     return lastMatchingElement(*this);
 }
 
-inline Element* HTMLCollection::traverseNextElement(Element& previous) const
-{
-    if (overridesItemAfter())
-        return virtualItemAfter(&previous);
-    if (shouldOnlyIncludeDirectChildren())
-        return nextMatchingChildElement(*this, previous);
-    return nextMatchingElement(*this, previous);
-}
-
 Element* HTMLCollection::traverseForwardToOffset(unsigned offset, Element& currentElement, unsigned& currentOffset) const
 {
     ASSERT(currentOffset < offset);
@@ -455,7 +446,9 @@ void HTMLCollection::supportedPropertyNames(Vector<String>& names)
     //      nor is in result, append element's name attribute value to result.
     // 3. Return result.
     HashSet<AtomicString> existingNames;
-    for (Element* element = traverseToFirstElement(); element; element = traverseNextElement(*element)) {
+    unsigned length = this->length();
+    for (unsigned i = 0; i < length; ++i) {
+        Element* element = item(i);
         const AtomicString& idAttribute = element->getIdAttribute();
         if (!idAttribute.isEmpty()) {
             HashSet<AtomicString>::AddResult addResult = existingNames.add(idAttribute);
@@ -484,7 +477,9 @@ void HTMLCollection::updateIdNameCache() const
         return;
 
     OwnPtrWillBeRawPtr<NamedItemCache> cache = NamedItemCache::create();
-    for (Element* element = traverseToFirstElement(); element; element = traverseNextElement(*element)) {
+    unsigned length = this->length();
+    for (unsigned i = 0; i < length; ++i) {
+        Element* element = item(i);
         const AtomicString& idAttrVal = element->getIdAttribute();
         if (!idAttrVal.isEmpty())
             cache->addElementWithId(idAttrVal, element);

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

@@ -125,8 +125,6 @@ protected:
     }
 
 private:
-    Element* traverseNextElement(Element& previous) const;
-
     void invalidateIdNameCacheMaps(Document* oldDocument = 0) const
     {
         if (!hasValidIdNameCache())