nsIXPConnect
this method now correctly deals with cases where the passed in jsobject already has an associated xpcom interface for the cases: 1) the jsobject has already been wrapped as an nsixpconnectwrappedjs.
... it *might* be possible to queryinterface the resulting interface pointer to nsixpconnectwrappedjs.
...2) the xpcom object is in fact an nsixpconnectwrappedjs and thus already has an underlying jsobject.
... it *might* be possible to queryinterface the nsixpconnectjsobjectholder returned by the method into an nsixpconnectwrappednative or an nsixpconnectwrappedjs.