that this is not strictly correct because
    // this is a cross-origin check but not a third-party check.
    if (win.parent == win || win.location.origin == win.top.location.origin) {
      return;
    }
  } catch (e) {
    // If we get a security error when accessing the top-level origin, this
    // shows that the window is in a cross-origin context. In this case, we can
    // proceed to apply the shim.
    if (e.name != "SecurityError") {
      throw e;
    }
  }

  const emptyMsg = cloneInto({ message: "" }, window);

  const idb = {
    open: () => win.Promise.reject(emptyMsg),
  };

  Object.defineProperty(win, "indexedDB", {
    value: cloneInto(idb, window, { cloneFunctions: true }),
  });
})();
PK