ServiceWorker: Introduce ServiceWorkerMessageEvent to replace MessageEvent (3/3).

Source/modules/serviceworkers/ServiceWorkerMessageEventInit.idl

Index: Source/modules/serviceworkers/ServiceWorkerMessageEventInit.idl
diff --git a/Source/modules/serviceworkers/ServiceWorkerMessageEventInit.idl b/Source/modules/serviceworkers/ServiceWorkerMessageEventInit.idl
new file mode 100644
index 0000000000000000000000000000000000000000..9c134ece7c14b44233fe7c3278cfd94a9b4ec5c7
--- /dev/null
+++ b/Source/modules/serviceworkers/ServiceWorkerMessageEventInit.idl
@@ -0,0 +1,13 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// https://slightlyoff.github.io/ServiceWorker/spec/service_worker/#serviceworkermessage-event-init-dictionary
+
+dictionary ServiceWorkerMessageEventInit : EventInit {
+    any data;
+    DOMString origin;
+    DOMString lastEventId;
+    (ServiceWorker or MessagePort)? source;
+    sequence<MessagePort> ports;
+};