IDL: Use Nullable for union type return value

Source/core/html/HTMLFormElement.cpp

Index: Source/core/html/HTMLFormElement.cpp
diff --git a/Source/core/html/HTMLFormElement.cpp b/Source/core/html/HTMLFormElement.cpp
index 6c69dd1946e14c0b665dc0989e943197860ab793..32bfe66ee5dd9b1f28c40b19f6178803fd34f0f1 100644
--- a/Source/core/html/HTMLFormElement.cpp
+++ b/Source/core/html/HTMLFormElement.cpp
@@ -817,7 +817,7 @@ void HTMLFormElement::copyNonAttributePropertiesFromElement(const Element& sourc
     HTMLElement::copyNonAttributePropertiesFromElement(source);
 }
 
-void HTMLFormElement::anonymousNamedGetter(const AtomicString& name, bool& returnValue0Enabled, RefPtrWillBeRawPtr<RadioNodeList>& returnValue0, bool& returnValue1Enabled, RefPtrWillBeRawPtr<Element>& returnValue1)
+void HTMLFormElement::anonymousNamedGetter(const AtomicString& name, Nullable<RefPtrWillBeRawPtr<RadioNodeList> >& returnValue0, Nullable<RefPtrWillBeRawPtr<Element> >& returnValue1)
 {
     // Call getNamedElements twice, first time check if it has a value
     // and let HTMLFormElement update its cache.
@@ -836,14 +836,12 @@ void HTMLFormElement::anonymousNamedGetter(const AtomicString& name, bool& retur
     ASSERT(!elements.isEmpty());
 
     if (elements.size() == 1) {
-        returnValue1Enabled = true;
-        returnValue1 = elements.at(0);
+        returnValue1.set(elements.at(0));
         return;
     }
 
     bool onlyMatchImg = !elements.isEmpty() && isHTMLImageElement(*elements.first());
-    returnValue0Enabled = true;
-    returnValue0 = radioNodeList(name, onlyMatchImg);
+    returnValue0.set(radioNodeList(name, onlyMatchImg));
 }
 
 void HTMLFormElement::setDemoted(bool demoted)