chromium/third_party/blink/web_tests/http/tests/dom/unthrottling-oopif-dirties-subframe.html

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

<style>
.spacer {
  height: 2000px;
}
</style>

<div class="spacer"></div>
<iframe id="iframe" src="http://localhost:8000/dom/resources/unthrottling-oopif-dirties-subframe-frame.html"></iframe>

<script>
async_test(t => {
  let iframe = document.getElementById("iframe");
  iframe.addEventListener("load", evt => {
    // rAF+timeout to make sure the iframe has been notified that it's throttled.
    requestAnimationFrame(() => {
      setTimeout(() => {
        document.scrollingElement.scrollTop = 10000;
        // rAF+timeout to wait for the unthrottling notification to be sent to the iframe.
        requestAnimationFrame(() => {
          setTimeout(() => {
            // Ask the iframe to rAF and respond.
            iframe.contentWindow.postMessage("", "*");
          });
        });
      });
    });
  });
  self.addEventListener("message", evt => {
    t.step(() => {
      assert_not_equals(evt.data, "TIMEOUT", "rAF never ran in iframe; did it get unthrottled?");
      assert_equals(evt.data, "SUCCESS", "Unknown failure.");
    });
    t.done();
  });
});
</script>