diff -r 000000000000 -r 6474c204b198 dom/audiochannel/nsIAudioChannelAgent.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/audiochannel/nsIAudioChannelAgent.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,142 @@
+/* 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/. */
+
+#include "nsISupports.idl"
+
+interface nsIDOMWindow;
+
+[uuid(194b55d9-39c0-45c6-b8ef-b8049f978ea5)]
+interface nsIAudioChannelAgentCallback : nsISupports
+{
+  /**
+   * Notified when the playable status of channel is changed.
+   *
+   * @param canPlay
+   *        Callback from agent to notify component of the playable status
+   *        of the channel. If canPlay is muted state, component SHOULD stop
+   *        playing media associated with this channel as soon as possible. if
+   *        it is faded state then the volume of media should be reduced.
+   */
+  void canPlayChanged(in long canPlay);
+
+  /**
+   * Notified when the window volume/mute is changed
+   */
+  void windowVolumeChanged();
+};
+
+/**
+ * This interface provides an agent for gecko components to participate
+ * in the audio channel service. Gecko components are responsible for
+ *   1. Indicating what channel type they are using (via the init() member
+ *      function).
+ *   2. Before playing, checking the playable status of the channel.
+ *   3. Notifying the agent when they start/stop using this channel.
+ *   4. Notifying the agent of changes to the visibility of the component using
+ *      this channel.
+ *
+ * The agent will invoke a callback to notify Gecko components of
+ *   1. Changes to the playable status of this channel.
+ */
+
+[uuid(2b0222a5-8f7b-49d2-9ab8-cd01b744b23e)]
+interface nsIAudioChannelAgent : nsISupports
+{
+  const long AUDIO_AGENT_CHANNEL_NORMAL             = 0;
+  const long AUDIO_AGENT_CHANNEL_CONTENT            = 1;
+  const long AUDIO_AGENT_CHANNEL_NOTIFICATION       = 2;
+  const long AUDIO_AGENT_CHANNEL_ALARM              = 3;
+  const long AUDIO_AGENT_CHANNEL_TELEPHONY          = 4;
+  const long AUDIO_AGENT_CHANNEL_RINGER             = 5;
+  const long AUDIO_AGENT_CHANNEL_PUBLICNOTIFICATION = 6;
+
+  const long AUDIO_AGENT_CHANNEL_ERROR              = 1000;
+
+  const long AUDIO_AGENT_STATE_NORMAL               = 0;
+  const long AUDIO_AGENT_STATE_MUTED                = 1;
+  const long AUDIO_AGENT_STATE_FADED                = 2;
+
+  /**
+   * Before init() is called, this returns AUDIO_AGENT_CHANNEL_ERROR.
+   */
+  readonly attribute long audioChannelType;
+
+  /**
+   * Initialize the agent with a channel type.
+   * Note: This function should only be called once.
+   *
+   * @param window
+   *    The window
+   * @param channelType
+   *    Audio Channel Type listed as above
+   * @param callback
+   *    1. Once the playable status changes, agent uses this callback function
+   *       to notify Gecko component.
+   *    2. The callback is allowed to be null. Ex: telephony doesn't need to
+   *       listen change of the playable status.
+   *    3. The AudioChannelAgent keeps a strong reference to the callback
+   *       object.
+   */
+  void init(in nsIDOMWindow window, in long channelType,
+            in nsIAudioChannelAgentCallback callback);
+
+  /**
+   * This method is just like init(), except the audio channel agent keeps a
+   * weak reference to the callback object.
+   *
+   * In order for this to work, |callback| must implement
+   * nsISupportsWeakReference.
+   */
+  void initWithWeakCallback(in nsIDOMWindow window, in long channelType,
+                            in nsIAudioChannelAgentCallback callback);
+
+  /**
+   * This method is just like init(), and specify the channel is associated
+   * with video.
+   *
+   * @param weak
+   *    true if weak reference should be hold.
+   */
+  void initWithVideo(in nsIDOMWindow window, in long channelType,
+                     in nsIAudioChannelAgentCallback callback, in boolean weak);
+
+  /**
+   * Notify the agent that we want to start playing.
+   * Note: Gecko component SHOULD call this function first then start to
+   *          play audio stream only when return value is true.
+   *
+   *
+   * @return
+   *    normal state: the agent has registered with audio channel service and
+   *          the component should start playback.
+   *    muted state: the agent has registered with audio channel service but
+   *          the component should not start playback.
+   *    faded state: the agent has registered with audio channel service the
+   *          component should start playback as well as reducing the volume.
+   */
+  long startPlaying();
+
+  /**
+   * Notify the agent we no longer want to play.
+   *
+   * Note : even if startPlaying() returned false, the agent would still be
+   *        registered with the audio channel service and receive callbacks for status changes.
+   *        So stopPlaying must still eventually be called to unregister the agent with the
+   *        channel service.
+   */
+  void stopPlaying();
+
+  /**
+   * Notify the agent of the visibility state of the window using this agent.
+   * @param visible
+   *    True if the window associated with the agent is visible.
+   */
+  void setVisibilityState(in boolean visible);
+
+  /**
+   * Retrieve the volume from the window.
+   */
+  readonly attribute float windowVolume;
+};
+