longtask-timing/shared-renderer/longtask-in-new-window.html

<!DOCTYPE HTML>
<meta charset=utf-8>
<title>LongTask Timing: long task in another window</title>
<body>

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<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;
              continue;
            }
            // If a longtask is observed, it must come from this window.
            assert_equals(entry.name, 'self');
          }
          // If we found the mark, then the other window longtask is done.
          if (markFound)
            t.done();
      })
  );
  observer.observe({entryTypes: ['mark', 'longtask']});

  window.onload = () => {
    // Open a window with a longtask.
    const other_window = window.open('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.
      self.performance.mark('mark1');
    }));
  };
}, 'A longtask in a frame from window.open is not reported in original frame');
</script>
</body>