LayoutTests/http/tests/fetch/clone-in-detached-frame.html

<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/js-test-resources/gc.js"></script>
<script>
  function with_iframe() {
      return new Promise((resolve) => {
          const frame = document.createElement("iframe");
          frame.src = "about:blank";
          frame.onload = () => resolve(frame);
          document.documentElement.appendChild(frame);
      });
  }

  promise_test(async (t) => {
      let frame = await with_iframe();
      const response = await frame.contentWindow.fetch("/resources/test.mp4");
      response.clone();
      frame.remove();
      frame = null;
      gc();
      response.clone();
  }, "Cloning response in a detached iframe should not crash");
</script>