Use new Traversal<HTML*Element> API in HTML code

Source/core/html/HTMLObjectElement.cpp

Index: Source/core/html/HTMLObjectElement.cpp
diff --git a/Source/core/html/HTMLObjectElement.cpp b/Source/core/html/HTMLObjectElement.cpp
index b6d1317f27ecf15dafaa119a591285c0fd8192c9..17f8fa7e4391db3769810b2f360ba65571d1d3ee 100644
--- a/Source/core/html/HTMLObjectElement.cpp
+++ b/Source/core/html/HTMLObjectElement.cpp
@@ -145,11 +145,7 @@ void HTMLObjectElement::parametersForPlugin(Vector<String>& paramNames, Vector<S
 
     // Scan the PARAM children and store their name/value pairs.
     // Get the URL and type from the params if we don't already have them.
-    for (Element* child = ElementTraversal::firstWithin(*this); child; child = ElementTraversal::nextSibling(*child)) {
-        if (!child->hasTagName(paramTag))
-            continue;
-
-        HTMLParamElement* p = toHTMLParamElement(child);
+    for (HTMLParamElement* p = Traversal<HTMLParamElement>::firstChild(*this); p; p = Traversal<HTMLParamElement>::nextSibling(*p)) {
         String name = p->name();
         if (name.isEmpty())
             continue;