implement related sw interface and register method

components/script/dom/webidls/ServiceWorker.webidl

@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// http://slightlyoff.github.io/ServiceWorker/spec/service_worker/#service-worker-obj
+//[Exposed=(Window,Worker)]
+[Pref="dom.serviceworker.enabled"]
+interface ServiceWorker : EventTarget {
+  readonly attribute USVString scriptURL;
+  readonly attribute ServiceWorkerState state;
+  //[Throws] void postMessage(any message/*, optional sequence<Transferable> transfer*/);
+
+  // event
+  attribute EventHandler onstatechange;
+};
+
+ServiceWorker implements AbstractWorker;
+
+enum ServiceWorkerState {
+  "installing",
+  "installed",
+  "activating",
+  "activated",
+  "redundant"
+};