| PASS ServiceWorkerGlobalScope: ExtendableMessageEvent Constructor | |
| PASS no initializer specified | |
| PASS `bubbles` is specified | |
| PASS `cancelable` is specified | |
| PASS `data` is specified | |
| PASS `origin` is specified | |
| PASS `lastEventId` is specified | |
| PASS `source` is specified | |
| PASS `ports` is specified | |
| PASS all initial values are specified | |