al empty document.
  openedWindow.location.href = url2;
  await waitForMessage(t, "loaded");
  assert_equals(openedWindow.history.length, 2,
    "history.length should increase after normal navigation away from non-initial empty document");
}, "location.href");

promise_test(async t => {
  // Open a new window with no URL, which will stay in the initial empty document until the navigation below.
  const openedWindow = windowOpenNoURL(t);

  // Navigate away from the initial empty document through location.a