▶ OK [expected TIMEOUT] /html/browsers/browsing-the-web/history-traversal/srcdoc/srcdoc-history-entries.html
  │   ▶ FAIL [expected NOTRUN] srcdoc history entries: the container window navigates
  │   └   → promise_test: Unhandled rejection with value: object "TypeError: iframe is null"
  │   ▶ FAIL [expected TIMEOUT] srcdoc history entries: the iframe itself navigates
  │   │   → assert_equals: expected 2 but got 1
  │   │ 
  │   │ @http://web-platform.test:8000/html/browsers/browsing-the-web/history-traversal/srcdoc/srcdoc-history-entries.html:28:16
  │   │ async*Test.prototype.step@http://web-platform.test:8000/resources/testharness.js:2638:25
  │   │ promise_test/tests.promise_tests</<@http://web-platform.test:8000/resources/testharness.js:738:36
  └   └ promise_test/tests.promise_tests<@http://web-platform.test:8000/resources/testharness.js:737:20