Use Traversal<>::firstAncestor() API more in the code base

Source/core/html/HTMLTextFormControlElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 682 matching lines @@
 }
 
 HTMLTextFormControlElement* enclosingTextFormControl(Node* container)
 {
     if (!container)
         return 0;
     Element* ancestor = container->shadowHost();
     return ancestor && isHTMLTextFormControlElement(*ancestor) && container->containingShadowRoot()->type() == ShadowRoot::UserAgentShadowRoot ? toHTMLTextFormControlElement(ancestor) : 0;
 }
 
-static const HTMLElement* parentHTMLElement(const Element* element)
-{
-    while (element) {
-        element = element->parentElement();
-        if (element && element->isHTMLElement())
-            return toHTMLElement(element);
-    }
-    return 0;
-}
-
 String HTMLTextFormControlElement::directionForFormData() const
 {
-    for (const HTMLElement* element = this; element; element = parentHTMLElement(element)) {
+    for (const HTMLElement* element = this; element; element = Traversal<HTMLElement>::firstAncestor(*element)) {
         const AtomicString& dirAttributeValue = element->fastGetAttribute(dirAttr);
         if (dirAttributeValue.isNull())
             continue;
 
         if (equalIgnoringCase(dirAttributeValue, "rtl") || equalIgnoringCase(dirAttributeValue, "ltr"))
             return dirAttributeValue;
 
         if (equalIgnoringCase(dirAttributeValue, "auto")) {
             bool isAuto;
             TextDirection textDirection = element->directionalityIfhasDirAutoAttribute(isAuto);
@@ skipping 242 matching lines @@
             Text* textNode = toText(node);
             size_t firstLineBreak = textNode->data().find('\n', isPivotNode ? pivotPosition.offsetInContainerNode() : 0);
             if (firstLineBreak != kNotFound)
                 return Position(textNode, firstLineBreak + 1);
         }
     }
     return endOfInnerText(textFormControl);
 }
 
 } // namespace Webcore