          "&import-rule" + "&type=font";
        let url_prefix = location.protocol + "//" + location.hostname + ":" + location.port;
        let css_referrer = url_prefix +
          "/common/security-features/subresource/stylesheet.py?id=" + id + "&type=font";
        let font_url = url_prefix + "/common/security-features/subresource/font.py" +
                       "?id=" + id + "&report-headers" + "&type=font";

        return new Promise(resolve => {
            let link = document.createElement("link