diff -r 000000000000 -r 6474c204b198 dom/webidl/AudioChannelManager.webidl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/webidl/AudioChannelManager.webidl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,32 @@
+/* -*- 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 AudioChannelManager : EventTarget {
+  /**
+   * Indicates whether the headphones are plugged in or not.
+   */
+  readonly attribute boolean headphones;
+
+  /**
+   * Fired when the headphones are plugged or unplugged.
+   *
+   * When the headphones are unplugged, we may start playing audio through the
+   * system's speakers.  Similarly, when headphones are plugged in, we may
+   * switch audio from speakers to headphones.
+   *
+   * If audio is currently playing in this window or in one of its children, we
+   * will fire this event before we switch the audio output from headphones to
+   * speakers (or vice versa).  This allows you to, for example, pause your
+   * window's audio when the headphones are unplugged.
+   */
+  attribute EventHandler onheadphoneschange;
+
+  /**
+   * Indicates which audio channel is used to adjust volume when pressing HW
+   * volume keys.
+   */
+  attribute DOMString volumeControlChannel;
+};