IDL: Use Nullable for union type return value

Source/core/html/HTMLOptionsCollection.cpp

 /*
  * Copyright (C) 2006, 2011, 2012 Apple Computer, Inc.
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 100 matching lines @@
 void HTMLOptionsCollection::setSelectedIndex(int index)
 {
     toHTMLSelectElement(ownerNode()).setSelectedIndex(index);
 }
 
 void HTMLOptionsCollection::setLength(unsigned length, ExceptionState& exceptionState)
 {
     toHTMLSelectElement(ownerNode()).setLength(length, exceptionState);
 }
 
-void HTMLOptionsCollection::namedGetter(const AtomicString& name, bool& returnValue0Enabled, RefPtrWillBeRawPtr<NodeList>& returnValue0, bool& returnValue1Enabled, RefPtrWillBeRawPtr<Element>& returnValue1)
+void HTMLOptionsCollection::namedGetter(const AtomicString& name, RefPtrWillBeRawPtr<NodeList>& returnValue0, RefPtrWillBeRawPtr<Element>& returnValue1)
 {
     WillBeHeapVector<RefPtrWillBeMember<Element> > namedItems;
     this->namedItems(name, namedItems);
 
     if (!namedItems.size())
         return;
 
     if (namedItems.size() == 1) {
-        returnValue1Enabled = true;
         returnValue1 = namedItems.at(0);
         return;
     }
 
     // FIXME: The spec and Firefox do not return a NodeList. They always return the first matching Element.
-    returnValue0Enabled = true;
     returnValue0 = StaticElementList::adopt(namedItems);
 }
 
 bool HTMLOptionsCollection::anonymousIndexedSetter(unsigned index, PassRefPtrWillBeRawPtr<HTMLOptionElement> value, ExceptionState& exceptionState)
 {
     HTMLSelectElement& base = toHTMLSelectElement(ownerNode());
     if (!value) { // undefined or null
         base.remove(index);
         return true;
     }
     base.setOption(index, value.get(), exceptionState);
     return true;
 }
 
 } //namespace