diff -r 000000000000 -r 6474c204b198 dom/webidl/GamepadButtonEvent.webidl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/webidl/GamepadButtonEvent.webidl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+/* -*- 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/.
+ */
+
+[Pref="dom.gamepad.non_standard_events.enabled",
+ Constructor(DOMString type, optional GamepadButtonEventInit eventInitDict)]
+interface GamepadButtonEvent : GamepadEvent
+{
+  readonly attribute unsigned long button;
+};
+
+dictionary GamepadButtonEventInit : GamepadEventInit
+{
+  unsigned long button = 0;
+};