IDL: Use Nullable for union type return value

Source/core/html/HTMLAllCollection.h

 /*
  * Copyright (C) 2009, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
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  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 #ifndef HTMLAllCollection_h
 #define HTMLAllCollection_h
 
+#include "bindings/core/v8/Nullable.h"
 #include "core/html/HTMLCollection.h"
 
 namespace blink {
 
 class HTMLAllCollection FINAL : public HTMLCollection {
 public:
     static PassRefPtrWillBeRawPtr<HTMLAllCollection> create(ContainerNode&, CollectionType);
     virtual ~HTMLAllCollection();
 
     Element* namedItemWithIndex(const AtomicString& name, unsigned index) const;
-    void namedGetter(const AtomicString& name, bool&, RefPtrWillBeRawPtr<NodeList>&, bool&, RefPtrWillBeRawPtr<Element>&);
+    void namedGetter(const AtomicString& name, Nullable<RefPtrWillBeRawPtr<NodeList> >&, Nullable<RefPtrWillBeRawPtr<Element> >&);
 
 private:
     explicit HTMLAllCollection(ContainerNode&);
 };
 
 DEFINE_TYPE_CASTS(HTMLAllCollection, LiveNodeListBase, collection, collection->type() == DocAll, collection.type() == DocAll);
 
 } // namespace blink
 
 #endif // HTMLAllCollection_h