[2] Web IDL (Second Edition) ( 版) http://heycam.github.io/webidl/#urlmismatcherror
歴史
[1] Make shared workers always key on constructor url and name · whatwg/html@b261d16 ( 版) https://github.com/whatwg/html/commit/b261d162b451a646d5597689f0b831a722a19182