propagate AVAILABLE_DEVICES_CHANGED event

JitsiConference.js

     this.startAudioMuted = false;
     this.startVideoMuted = false;
     this.startMutedPolicy = {audio: false, video: false};
+    this.availableDevices = {
+        audio: undefined,
+        video: undefined
+    };
 }
 
 /**
         }
     });
 
+    conference.rtc.addListener(RTCEvents.AVAILABLE_DEVICES_CHANGED, function (devices) {
+        conference.room.updateDeviceAvailability(devices);
+    });
+    conference.room.addPresenceListener("devices", function (data, from) {
+        var isAudioAvailable = false;
+        var isVideoAvailable = false;
+        data.children.forEach(function (config) {
+            if (config.tagName === 'audio') {
+                isAudioAvailable = config.value === 'true';
+            }
+            if (config.tagName === 'video') {
+                isVideoAvailable = config.value === 'true';
+            }
+        });
+
+        var availableDevices;
+        if (conference.myUserId() === from) {
+            availableDevices = conference.availableDevices;
+        } else {
+            var participant = conference.getParticipantById(from);
+            if (!participant) {
+                return;
+            }
+
+            availableDevices = participant._availableDevices;
+        }
+
+        var updated = false;
+
+        if (availableDevices.audio !== isAudioAvailable) {
+            updated = true;
+            availableDevices.audio = isAudioAvailable;
+        }
+
+        if (availableDevices.video !== isVideoAvailable) {
+            updated = true;
+            availableDevices.video = isVideoAvailable;
+        }
+
+        if (updated) {
+            conference.eventEmitter.emit(JitsiConferenceEvents.AVAILABLE_DEVICES_CHANGED, from, availableDevices);
+        }
+    });
+
     if(conference.statistics) {
         //FIXME: Maybe remove event should not be associated with the conference.
         conference.statistics.addAudioLevelListener(function (ssrc, level) {
             function () {
                 conference.statistics.dispose();
             });
-        // FIXME: Maybe we should move this.
-        // RTC.addListener(RTCEvents.AVAILABLE_DEVICES_CHANGED, function (devices) {
-        //     conference.room.updateDeviceAvailability(devices);
-        // });
 
         conference.room.addListener(XMPPEvents.PEERCONNECTION_READY,
             function (session) {

JitsiConferenceEvents.js

      * Indicates that to proceed with screen sharing
      * browser extension must be installed first.
      */
-    FIREFOX_EXTENSION_NEEDED: "conference.firefoxExtensionRequired"
+    FIREFOX_EXTENSION_NEEDED: "conference.firefoxExtensionRequired",
+    /**
+     * Indicates that available devices changed.
+     */
+    AVAILABLE_DEVICES_CHANGED: "conference.availableDevicesChanged"
 };
 
 module.exports = JitsiConferenceEvents;

JitsiParticipant.js

     this._tracks = [];
     this._role = 'none';
     this._status = null;
+    this._availableDevices = {
+        audio: undefined,
+        video: undefined
+    };
 }
 
 /**

doc/API.md

         - START_MUTED_POLICY_CHANGED - notifies that all new participants will join with muted audio/video stream (parameters - JS object with 2 properties - audio(boolean), video(boolean))
         - STARTED_MUTED - notifies that the local user has started muted
         - FIREFOX_EXTENSION_NEEDED - notifies that browser extension must be installed to proceed with screen sharing (parameters - extension url(string))
+        - AVAILABLE_DEVICES_CHANGED - notifies that available participant devices changed (camera or microphone was added or removed) (parameters - id(string), devices(JS object with 2 properties - audio(boolean), video(boolean)))
 
     2. connection
         - CONNECTION_FAILED - indicates that the server connection failed.

modules/xmpp/xmpp.js

 //        broadcastLocalVideoType,
 //        StreamEventTypes.EVENT_TYPE_LOCAL_CHANGED
 //    );
-//    RTC.addListener(RTCEvents.AVAILABLE_DEVICES_CHANGED, function (devices) {
-//        XMPP.addToPresence("devices", devices);
-//    });
 //}
 
 function XMPP(options) {

service/xmpp/XMPPEvents.js

     // Designates an event indicating that we should join the conference with
     // audio and/or video muted.
     START_MUTED_FROM_FOCUS: "xmpp.start_muted_from_focus",
-    // Designates an event indicating that a remote participant's available
-    // devices (whether he supports a audio and/or video) changed.
-    // Note: currently this event fires every time we receive presence from
-    // someone (regardless of whether or not the devices changed).
-    DEVICE_AVAILABLE: "xmpp.device_available",
 
 
     PEERCONNECTION_READY: "xmpp.peerconnection_ready",