IDL: Use Nullable for union type return value

Source/core/html/HTMLAllCollection.h

Index: Source/core/html/HTMLAllCollection.h
diff --git a/Source/core/html/HTMLAllCollection.h b/Source/core/html/HTMLAllCollection.h
index d099253d1bc9b9ae6fc70e5137db9c5e09bd2fa8..300e4ebf32a417aa4c429b93fc411a9381a1dfab 100644
--- a/Source/core/html/HTMLAllCollection.h
+++ b/Source/core/html/HTMLAllCollection.h
@@ -26,6 +26,7 @@
 #ifndef HTMLAllCollection_h
 #define HTMLAllCollection_h
 
+#include "bindings/core/v8/Nullable.h"
 #include "core/html/HTMLCollection.h"
 
 namespace blink {
@@ -36,7 +37,7 @@ public:
     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&);