IDL: Use Nullable for union type return value

Source/core/html/HTMLFormControlsCollection.h

Index: Source/core/html/HTMLFormControlsCollection.h
diff --git a/Source/core/html/HTMLFormControlsCollection.h b/Source/core/html/HTMLFormControlsCollection.h
index fe5ca7365f1bfc9cd331591e577e45846dff8f48..3fa82cd573931bc5b23302219502e1ed3e72dc8f 100644
--- a/Source/core/html/HTMLFormControlsCollection.h
+++ b/Source/core/html/HTMLFormControlsCollection.h
@@ -24,6 +24,7 @@
 #ifndef HTMLFormControlsCollection_h
 #define HTMLFormControlsCollection_h
 
+#include "bindings/core/v8/Nullable.h"
 #include "core/html/FormAssociatedElement.h"
 #include "core/html/HTMLCollection.h"
 #include "core/html/RadioNodeList.h"
@@ -44,7 +45,7 @@ public:
     virtual ~HTMLFormControlsCollection();
 
     virtual Element* namedItem(const AtomicString& name) const OVERRIDE;
-    void namedGetter(const AtomicString& name, bool& radioNodeListEnabled, RefPtrWillBeRawPtr<RadioNodeList>&, bool& elementEnabled, RefPtrWillBeRawPtr<Element>&);
+    void namedGetter(const AtomicString& name, Nullable<RefPtrWillBeRawPtr<RadioNodeList> >&, Nullable<RefPtrWillBeRawPtr<Element> >&);
 
     virtual void trace(Visitor*) OVERRIDE;