This is a testharness.js-based test. FAIL postMessage from ServiceWorker to Client assert_equals: message events assert_unreached: unregister should use MessageEvent interface. expected function "function MessageEvent() { [native code] }" but got function "function ServiceWorkerMessageEvent() { [native code] }" not fail: Failed to get a ServiceWorkerRegistration: The URL protocol of the current origin ('file://') is not supported. Reached unreachable code Harness: the test ran to completion.