nsIExceptionService Interface

 Installs an "exception provider" which is capable of
        translating an nsresult into an exception.  This enables
        error providers to return simple nsresults and only provide
        rich errors when specifically requested. It also has the
        advantage of allowing code like the DOM to handle all errors
        in a single function rather than at each XPCOM entry point.
        NOTE: This interface must be thread-safe - it will be called
        on whatever thread needs the error translation performed.*/

void registerExceptionProvider(in nsIExceptionProvider provider, in PRUint32 moduleCode)