Add jsdocs and optimize

JitsiConference.js

     this.eventEmitter.emit(JitsiConferenceEvents.DISPLAY_NAME_CHANGED, id, displayName);
 };
 
+/**
+ * Notifies this JitsiConference that a JitsiRemoteTrack was added (into the
+ * ChatRoom of this JitsiConference).
+ *
+ * @param {JitsiRemoteTrack} track the JitsiRemoteTrack which was added to this
+ * JitsiConference
+ */
 JitsiConference.prototype.onTrackAdded = function (track) {
     var id = track.getParticipantId();
     var participant = this.getParticipantById(id);
         return;
     }
 
-    // add track to JitsiParticipant
+    // Add track to JitsiParticipant.
     participant._tracks.push(track);
 
     var emitter = this.eventEmitter;
     track.addEventListener(
         JitsiTrackEvents.TRACK_AUDIO_LEVEL_CHANGED,
         function (audioLevel) {
-            emitter.emit(JitsiConferenceEvents.TRACK_AUDIO_LEVEL_CHANGED, id, audioLevel);
+            emitter.emit(
+                JitsiConferenceEvents.TRACK_AUDIO_LEVEL_CHANGED,
+                id,
+                audioLevel);
         }
     );
 
-    this.eventEmitter.emit(JitsiConferenceEvents.TRACK_ADDED, track);
+    emitter.emit(JitsiConferenceEvents.TRACK_ADDED, track);
 };
 
 JitsiConference.prototype.updateDTMFSupport = function () {

modules/RTC/RTC.js

     this.options = options || {};
     room.addPresenceListener("videomuted", function (values, from) {
         var videoTrack = self.getRemoteVideoTrack(from);
-        if (!videoTrack) {
-            return;
+        if (videoTrack) {
+            videoTrack.setMute(values.value == "true");
         }
-        videoTrack.setMute(values.value == "true");
     });
     room.addPresenceListener("audiomuted", function (values, from) {
         var audioTrack = self.getRemoteAudioTrack(from);
     }
 };
 
+/**
+ * Initializes a new JitsiRemoteTrack instance with the data provided by (a)
+ * ChatRoom to XMPPEvents.REMOTE_TRACK_ADDED.
+ *
+ * @param {Object} event the data provided by (a) ChatRoom to
+ * XMPPEvents.REMOTE_TRACK_ADDED to (a)
+ */
 RTC.prototype.createRemoteTrack = function (event) {
     var ownerJid = event.owner;
     var remoteTrack = new JitsiRemoteTrack(
         this,  ownerJid, event.stream,    event.track,
         event.mediaType, event.videoType, event.ssrc, event.muted);
     var resource = Strophe.getResourceFromJid(ownerJid);
-    if(!this.remoteTracks[resource]) {
-        this.remoteTracks[resource] = {};
-    }
+    var remoteTracks
+        = this.remoteTracks[resource] || (this.remoteTracks[resource] = {});
     var mediaType = remoteTrack.getType();
-    if (this.remoteTracks[resource][mediaType]) {
-        logger.warn(
-            "Overwriting remote track !", resource, mediaType);
+    if (remoteTracks[mediaType]) {
+        logger.warn("Overwriting remote track!", resource, mediaType);
     }
-    this.remoteTracks[resource][mediaType] = remoteTrack;
+    remoteTracks[mediaType] = remoteTrack;
     return remoteTrack;
 };