 new window that has not committed
// any real load in its frame, outside of the initial empty document. The two
// tests below vary depending on whether there is a pending navigation in the
// frame or not.
const runTest = (description, createNewPopup) => {
  promise_test(async test => {
    // Open a same-origin window with a different CSP.
    const executor_path =
      "/html/browsers/sandboxing/resources/execute-postmessage.html?pipe=";
    const csp = "|header(Content-Security-Policy, " +
           