chromium/third_party/blink/web_tests/external/wpt/html/browsers/browsing-the-web/unloading-documents/unload/unload-main-frame-cross-origin.window.js

// META: title=Unload runs in main frame when navigating cross-origin.
// META: script=/common/dispatcher/dispatcher.js
// META: script=/common/get-host-info.sub.js
// META: script=/common/utils.js
// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js

promise_test(async t => {
  const rcHelper = new RemoteContextHelper();

  const rc1 = await rcHelper.addWindow();

  t.add_cleanup(() => localStorage.removeItem('unload'));

  // Initialize storage and add "unload" event handler.
  await rc1.executeScript(() => {
    localStorage.setItem('unload', 'not yet');
    addEventListener('unload', () => {
      localStorage.setItem('unload', 'ran');
    });
  });

  // Navigate away.
  const rc2 = await rc1.navigateToNew(
      {extraRemoteContextConfig: {origin: 'HTTP_REMOTE_ORIGIN'}});

  // Navigate back.
  await rc2.historyBack();

  // Test that the unload handler wrote to storage.
  // Running it in the remote context after going back should ensure that the
  // navigation (and therefore the unload handler) has completed.
  assert_equals(
      await rc1.executeScript(() => localStorage.getItem('unload')), 'ran');
});