hed into a same-origin Document that isn't this Document -->
<iframe id="block6"></iframe>
<script nonce="abc">
  async_test(t => {
    var d = document.createElement("div");
    d.setAttribute("onclick", "void(0);");
    var events = 0;
    d.addEventListener('securitypolicyviolation', t.step_func(e => {
      events++;
      assert_equals(e.blockedURI, "inline");
      assert_equals(e.target, d);
    }));
    document.querySelector('#block6').contentDocument.addEventListener('securitypolicyviolation', t.s