Use new Traversal<HTML*Element> API more in accessibility

Source/core/accessibility/AXRenderObject.cpp

Index: Source/core/accessibility/AXRenderObject.cpp
diff --git a/Source/core/accessibility/AXRenderObject.cpp b/Source/core/accessibility/AXRenderObject.cpp
index 7d8d28ff690d9b77e443402cfff5bb5e7a62e60c..a34edf8c45236c69e2937fbb421ab99453d695be 100644
--- a/Source/core/accessibility/AXRenderObject.cpp
+++ b/Source/core/accessibility/AXRenderObject.cpp
@@ -2156,11 +2156,11 @@ void AXRenderObject::addImageMapChildren()
     if (!map)
         return;
 
-    for (Element* current = ElementTraversal::firstWithin(*map); current; current = ElementTraversal::next(*current, map)) {
+    for (HTMLAreaElement* area = Traversal<HTMLAreaElement>::firstWithin(*map); area; area = Traversal<HTMLAreaElement>::next(*area, map)) {
         // add an <area> element for this child if it has a link
-        if (isHTMLAreaElement(*current) && current->isLink()) {
+        if (area->isLink()) {
             AXImageMapLink* areaObject = toAXImageMapLink(axObjectCache()->getOrCreate(ImageMapLinkRole));
-            areaObject->setHTMLAreaElement(toHTMLAreaElement(current));
+            areaObject->setHTMLAreaElement(area);
             areaObject->setHTMLMapElement(map);
             areaObject->setParent(this);
             if (!areaObject->accessibilityIsIgnored())