diff -r 000000000000 -r 6474c204b198 dom/webidl/DataContainerEvent.webidl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/webidl/DataContainerEvent.webidl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,30 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/.
+ */
+
+interface nsIVariant;
+
+[ChromeOnly]
+interface DataContainerEvent : Event {
+  /**
+   * Return the data associated with the given key.
+   *
+   * @param  key  the key
+   * @return      the data associated with the key
+   */
+  nsIVariant? getData(DOMString? key);
+
+  /**
+   * Set the data for the given key.
+   *
+   * @param  key   the data key
+   * @param  data  the data
+   * @throws       NS_ERROR_UNEXPECTED if the method is called during event
+   *               dispatch
+   */
+  [Throws]
+  void setData(DOMString? key, any data);
+};
+