add popstateevent, hashchangeevent, pagetransitionevent

components/script/dom/webidls/PopStateEvent.webidl

@@ -0,0 +1,13 @@
+/* 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/. */
+
+// https://html.spec.whatwg.org/multipage/#the-popstateevent-interface
+[Constructor(DOMString type, optional PopStateEventInit eventInitDict)/*, Exposed=(Window,Worker)*/]
+interface PopStateEvent : Event {
+  readonly attribute any state;
+};
+
+dictionary PopStateEventInit : EventInit {
+  any state = null;
+};