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Test Info: Warnings

<meta charset=utf-8>
<title>LongTask Timing: long task in another window</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
/* This test should pass even when windows share a single renderer process.
This window opens a new window which contains a longtask. We test that the
longtask from the new window is not observed by the observer of this window. */
async_test(t => {
assert_implements(window.PerformanceLongTaskTiming, 'Longtasks are not supported.');
const observer = new PerformanceObserver(
t.step_func(function (entryList) {
const entries = entryList.getEntries();
let markFound = false;
for (let i = 0; i < entries.length; ++i) {
const entry = entries[i];
// We do not expect to observe longtasks but the work being made in this window may produce a longtask.
assert_true(entry.entryType === 'longtask' ||
entry.entryType === 'mark');
if (entry.entryType === 'mark') {
markFound = true;
// If a longtask is observed, it must come from this window.
assert_equals(, 'self');
// If we found the mark, then the other window longtask is done.
if (markFound)
observer.observe({entryTypes: ['mark', 'longtask']});
window.onload = () => {
// Open a window with a longtask.
const other_window ='resources/frame-with-longtask.html');
window.addEventListener('message', t.step_func(e => {
// Do a mark (after the other window's longtask) to fire the callback.
}, 'A longtask in a frame from is not reported in original frame');