diff -r 000000000000 -r 6474c204b198 dom/bindings/mozwebidlcodegen/test/TestEvent.webidl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/bindings/mozwebidlcodegen/test/TestEvent.webidl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+interface EventTarget {
+  void addEventListener();
+};
+
+interface Event {};
+
+callback EventHandlerNonNull = any (Event event);
+typedef EventHandlerNonNull? EventHandler;
+
+[NoInterfaceObject]
+interface TestEvent : EventTarget {
+  attribute EventHandler onfoo;
+};