The CustomEvent interface should be exposed on the view, like Event, UIEvent, etc.
Do you have a lionk to the spec that says it has to be exposed on the view?
No, it's not part of a spec, it's part of the de-facto standard of exposing most DOM interfaces so people can extend them for things such as implementing features for compatibility with future APIs and to use for feature detection, in the case of events (if (self.CustomEvent) { ... }).
<http://www.w3.org/TR/2011/WD-DOM-Level-3-Events-20110531/#webidl-events-CustomEvent> doesn't have a [NoInterfaceObject] attribute, which per WebIDL spec means that the interface object should be exposed on the global object. This is in an informative part of the spec, and I don't know if there is anything normative, but we certainly follow the practice of exposing interface objects on DOMWindow in general.
OK, great. Thanks for the explanation.
This got fixed yesterday. *** This bug has been marked as a duplicate of bug 67248 ***