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<!doctype html>
<title>enumerateDevices() with navigation</title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
'use strict';
const blank_url = '/common/blank.html';
const search2 = '?2';
function promise_new_task(t) {
return new Promise(resolve => t.step_timeout(resolve, 0));
function promise_event(target, name) {
return new Promise(resolve => target[`on${name}`] = resolve);
promise_test(async t => {
// Gecko persists only toplevel documents, so load documents in a toplevel.
await test_driver.bless('');
const proxy =;
t.add_cleanup(() => proxy.close());
await promise_event(proxy, 'pageshow');
const devices = proxy.navigator.mediaDevices;
// Use another task so that another load creates a new session history entry.
await promise_new_task(t);
proxy.location = blank_url + search2;
await promise_event(proxy, 'pagehide');
// Use another task to ensure the first subdocument is no longer fully
// active and proxy refers to the realm of the second document.
await promise_new_task(t);
assert_equals(, search2, 'navigated search');
// Enumerate from the inactive first Window.
const promise_enumerate = devices.enumerateDevices();
// `then()` is used rather than static Promise methods because microtasks
// for `PromiseResolve()` do not run when Promises from inactive realms are
// involved. Whether microtasks for `then()` run depends on the realm of
// the handler rather than the realm of the Promise.
// Don't use `finally()`, because it uses `PromiseResolve()` and so
// microtasks don't run.
let promise_state = 'pending';
promise_enumerate.then(() => promise_state = 'resolved',
() => promise_state = 'rejected');
// Enumerate in the active second Window to provide enough time to check
// that the Promise from the inactive Window does not settle.
await proxy.navigator.mediaDevices.enumerateDevices();
await promise_event(proxy, 'pagehide');
// enumerateDevices() Promise resolution is triggered only in parallel
// steps, so manipulation of the Promise (if the first document was
// persisted) would occur through a queued task, which would run after
// the pagehide event is dispatched and so after the associated
// microtask that runs the following assert.
assert_equals(promise_state, 'pending', 'Promise state while inactive');
// If the first document is restored, then that will occur immediately after
// pagehide (and associated microtasks), before the next global task is run.
await promise_new_task(t);
if (proxy.navigator.mediaDevices == devices) {
// The first document was persisted and restored.
assert_equals(, '', 'history search');
await promise_enumerate;
} else {
// The first document was not restored, but gets re-fetched.
await t.step_wait(() => == '', 'navigation');
assert_not_equals(proxy.navigator.mediaDevices, devices, 'new realm')
await proxy.navigator.mediaDevices.enumerateDevices();
assert_equals(promise_state, 'pending', 'Promise state after discard');
}, 'enumerateDevices with navigation');