2) added where I was not checking for JSVAL_NULL from brendan. 3) got rid of 'xpcom32' references. 4) added nsIEcho::ReturnInterface as a loopback for testing the above. 5) removed some redundant retval setting code. git-svn-id: svn://10.0.0.236/trunk@34734 18797224-902f-48f8-a5cc-f745e15eee43