IDL: Enumeration support in union types

Source/core/testing/UnionTypesTest.idl

Index: Source/core/testing/UnionTypesTest.idl
diff --git a/Source/core/testing/UnionTypesTest.idl b/Source/core/testing/UnionTypesTest.idl
index 23e0c93c365c552af0e0c90e9b5a447b6f5361e5..d6cef1543fd399abcb0548f65db9e33449af394c 100644
--- a/Source/core/testing/UnionTypesTest.idl
+++ b/Source/core/testing/UnionTypesTest.idl
@@ -8,6 +8,7 @@
     attribute (double or DOMString or DOMString[]) doubleOrStringOrStringArrayAttribute;
 
     DOMString doubleOrStringArg((double or DOMString) arg);
+    DOMString doubleOrInternalEnumArg((double or InternalEnum) arg);
 
     [ImplementedAs=doubleOrStringArg] DOMString doubleOrStringDefaultDoubleArg(optional (double or DOMString) arg = 3.14);
     [ImplementedAs=doubleOrStringArg] DOMString doubleOrStringDefaultStringArg(optional (double or DOMString) arg = "foo");