diff -r 000000000000 -r 6474c204b198 dom/webidl/TextTrackList.webidl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/webidl/TextTrackList.webidl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,25 @@
+/* -*- 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/.
+ *
+ * The origin of this IDL file is
+ * http://www.whatwg.org/specs/web-apps/current-work/#texttracklist
+ */
+
+[Pref="media.webvtt.enabled"]
+interface TextTrackList : EventTarget {
+  readonly attribute unsigned long length;
+  getter TextTrack (unsigned long index);
+  TextTrack? getTrackById(DOMString id);
+
+           attribute EventHandler onchange;
+           attribute EventHandler onaddtrack;
+           attribute EventHandler onremovetrack;
+};
+
+// Mozilla extensions
+partial interface TextTrackList {
+  [ChromeOnly]
+  readonly attribute HTMLMediaElement? mediaElement;
+};