Have ElementTraversal / NodeTraversal's next() methods take a reference

Source/core/html/HTMLObjectElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 104 matching lines @@
 inline const HTMLObjectElement* toHTMLObjectElement(const FormAssociatedElement* element)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!element || !element->isFormControlElement());
     const HTMLObjectElement* objectElement = static_cast<const HTMLObjectElement*>(element);
     // We need to assert after the cast because FormAssociatedElement doesn't
     // have hasTagName.
     ASSERT_WITH_SECURITY_IMPLICATION(!objectElement || objectElement->hasTagName(HTMLNames::objectTag));
     return objectElement;
 }
 
+inline const HTMLObjectElement& toHTMLObjectElement(const FormAssociatedElement& element)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(!element.isFormControlElement());
+    const HTMLObjectElement& objectElement = static_cast<const HTMLObjectElement&>(element);
+    // We need to assert after the cast because FormAssociatedElement doesn't
+    // have hasTagName.
+    ASSERT_WITH_SECURITY_IMPLICATION(objectElement.hasTagName(HTMLNames::objectTag));
+    return objectElement;
+}
+
 }
 
 #endif