Implement Referrer-Policy header for workers

third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/referrer-policy-iframe.html

 <script src="../../resources/get-host-info.js"></script>
 <script>
 function check_referer(url, expected_referer) {
   return fetch(url)
     .then(function(res) { return res.json(); })
     .then(function(headers) {
         if (headers['Referer'] === expected_referer) {
           return Promise.resolve();
         } else {
           return Promise.reject('Referer for ' + url + ' must be ' +
                                 expected_referer + ' but got ' +
                                 headers['Referer']);
         }
       });
 }
 
 window.addEventListener('message', function(evt) {
     var host_info = get_host_info();
     var port = evt.ports[0];
     check_referer('request-headers.php?ignore=true',
                   host_info['HTTP_ORIGIN'] +
-                  '/serviceworker/resources/referer-iframe.html')
-      .then(function() {
-          return check_referer(
-              'request-headers.php',
-              host_info['HTTP_ORIGIN'] +
-              '/serviceworker/resources/referer-iframe.html');
-        })
+                  '/serviceworker/resources/referrer-policy-iframe.html')
       .then(function() {
           return check_referer(
               'request-headers.php?url=request-headers.php',
-              host_info['HTTP_ORIGIN'] +
-              '/serviceworker/resources/fetch-rewrite-worker.js');
+              host_info['HTTP_ORIGIN'] + '/');
         })
       .then(function() { port.postMessage({results: 'finish'}); })
       .catch(function(e) { port.postMessage({results: 'failure:' + e}); });
   });
 </script>