[WIP] Move Web Notifications to a WebFrame-less code path (Blink).

LayoutTests/fast/notifications/resources/notification-replace.js

+if (self.importScripts) {
+    importScripts('../../../resources/js-test.js');
+    importScripts('notification-worker.js');
+}
+
 function runTest()
 {
     var notification = new Notification("Notification", {
         tag: "my-notification"
     });
 
     notification.addEventListener("show", function() {
         testPassed("notification.onshow() has been called.");
         var updatedNotification = new Notification("Notification 2", {
             tag: "my-notification"
         });
 
         updatedNotification.addEventListener("show", function() {
             testPassed("updatedNotification.onshow() has been called.");
-            if (window.testRunner)
-                testRunner.notifyDone();
+            finishJSTest();
         });
     });
 }