ServiceWorker: Stabilize install-phase-event-waituntil.html

LayoutTests/http/tests/serviceworker/resources/test-helpers.js

 // Adapter for testharness.js-style tests with Service Workers
 
 // Can only be used with a worker that installs successfully, since it
 // first registers to acquire a ServiceWorkerRegistration object to
 // unregister.
 // FIXME: Use getRegistration() when implemented.
 function service_worker_unregister_and_register(test, url, scope) {
   if (!scope || scope.length == 0)
     return Promise.reject(new Error('tests must define a scope'));
 
@@ skipping 47 matching lines @@
     });
   iframe.src = '';
   iframe.remove();
   return saw_unload;
 }
 
 function normalizeURL(url) {
   return new URL(url, document.location).toString().replace(/#.*$/, '');
 }
 
+function get_newest_worker(registration) {
+  if (!registration) {
+    return Promise.reject(new Error(
+        'get_newest_worker must be passed a ServiceWorkerRegistration'));
+  }
+  if (registration.installing)
+    return Promise.resolve(registration.installing);
+  if (registration.waiting)
+    return Promise.resolve(registration.waiting);
+  if (registration.active)
+    return Promise.resolve(registration.active);
+  return Promise.reject(new Error(
+      'registration must have at least one version'));
+}
+
 function wait_for_update(test, registration) {
   if (!registration || registration.unregister == undefined) {
     return Promise.reject(new Error(
         'wait_for_update must be passed a ServiceWorkerRegistration'));
   }
 
   return new Promise(test.step_func(function(resolve) {
       registration.addEventListener('updatefound', test.step_func(function() {
           resolve(registration.installing);
       }));
@@ skipping 107 matching lines @@
         HTTPS_ORIGIN: 'https://' + ORIGINAL_HOST + ':' + HTTPS_PORT,
         HTTP_REMOTE_ORIGIN: 'http://' + REMOTE_HOST + ':' + HTTP_PORT,
         HTTPS_REMOTE_ORIGIN: 'https://' + REMOTE_HOST + ':' + HTTPS_PORT,
         UNAUTHENTICATED_ORIGIN: 'http://' + UNAUTHENTICATED_HOST + ':' + HTTP_PORT
     };
 }
 
 function base_path() {
     return location.pathname.replace(/\/[^\/]*$/, '/');
 }