IDL: Use Nullable for union type return value

Source/core/html/HTMLFormControlsCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. 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 175 matching lines @@
                 cache->addElementWithId(idAttrVal, element);
             if (!nameAttrVal.isEmpty() && idAttrVal != nameAttrVal && !foundInputElements.contains(nameAttrVal.impl()))
                 cache->addElementWithName(nameAttrVal, element);
         }
     }
 
     // Set the named item cache last as traversing the tree may cause cache invalidation.
     setNamedItemCache(cache.release());
 }
 
-void HTMLFormControlsCollection::namedGetter(const AtomicString& name, bool& radioNodeListEnabled, RefPtrWillBeRawPtr<RadioNodeList>& radioNodeList, bool& elementEnabled, RefPtrWillBeRawPtr<Element>& element)
+void HTMLFormControlsCollection::namedGetter(const AtomicString& name, RefPtrWillBeRawPtr<RadioNodeList>& radioNodeList, RefPtrWillBeRawPtr<Element>& element)
 {
     WillBeHeapVector<RefPtrWillBeMember<Element> > namedItems;
     this->namedItems(name, namedItems);
 
     if (namedItems.isEmpty())
         return;
 
     if (namedItems.size() == 1) {
-        elementEnabled = true;
         element = namedItems.at(0);
         return;
     }
 
-    radioNodeListEnabled = true;
     radioNodeList = ownerNode().radioNodeList(name);
 }
 
 void HTMLFormControlsCollection::supportedPropertyNames(Vector<String>& names)
 {
     // http://www.whatwg.org/specs/web-apps/current-work/multipage/common-dom-interfaces.html#htmlformcontrolscollection-0:
     // The supported property names consist of the non-empty values of all the id and name attributes
     // of all the elements represented by the collection, in tree order, ignoring later duplicates,
     // with the id of an element preceding its name if it contributes both, they differ from each
     // other, and neither is the duplicate of an earlier entry.
@@ skipping 17 matching lines @@
     }
 }
 
 void HTMLFormControlsCollection::trace(Visitor* visitor)
 {
     visitor->trace(m_cachedElement);
     HTMLCollection::trace(visitor);
 }
 
 }