fix(DataChannels):Moves last n list handling to RTC

modules/RTC/DataChannels.js

     peerConnection.ondatachannel = this.onDataChannel.bind(this);
     this.eventEmitter = emitter;
 
-    this._lastNEndpoints = null;
     this._dataChannels = [];
 
     // Sample code for opening new data channel from Jitsi Meet to the bridge.
                     newValue);
             } else if (colibriClass === 'LastNEndpointsChangeEvent') {
                 // The new/latest list of last-n endpoint IDs.
-
-                self._lastNEndpoints = obj.lastNEndpoints;
+                const lastNEndpoints = obj.lastNEndpoints;
 
                 // The list of endpoint IDs which are entering the list of
                 // last-n at this time i.e. were not in the old list of last-n
                 // endpoint IDs.
                 const endpointsEnteringLastN = obj.endpointsEnteringLastN;
 
-                logger.info(
-                    'Data channel new last-n event: ',
-                        self._lastNEndpoints, endpointsEnteringLastN, obj);
+                logger.info('Data channel new last-n event: ',
+                    lastNEndpoints, endpointsEnteringLastN, obj);
                 self.eventEmitter.emit(RTCEvents.LASTN_ENDPOINT_CHANGED,
-                    self._lastNEndpoints, endpointsEnteringLastN, obj);
+                    lastNEndpoints, endpointsEnteringLastN, obj);
             } else if (colibriClass === 'EndpointMessage') {
                 self.eventEmitter.emit(
                     RTCEvents.ENDPOINT_MESSAGE_RECEIVED, obj.from,
     logger.log(`Channel lastN set to: ${value}`);
 };
 
-/**
- * Indicates if the endpoint id is currently included in the last N.
- *
- * @param id the endpoint id that we check for last N
- * @returns {boolean} {true} if the endpoint id is in the last N or if we
- * haven't initialised the last N array yet and {false} otherwise
- */
-DataChannels.prototype.isInLastN = function (id) {
-    return !this._lastNEndpoints // lastNEndpoints not initialised yet
-        || this._lastNEndpoints.indexOf(id) > -1;
-};
-
 module.exports = DataChannels;

modules/RTC/RTC.js

         if (this.options.config.openSctp) {
             this.dataChannels = new DataChannels(peerconnection,
                 this.eventEmitter);
+
             this._dataChannelOpenListener = () => {
                 // mark that dataChannel is opened
                 this.dataChannelsOpen = true;
             };
             this.addListener(RTCEvents.DATA_CHANNEL_OPEN,
                 this._dataChannelOpenListener);
+
+            this.addListener(RTCEvents.LASTN_ENDPOINT_CHANGED,
+                lastNEndpoints => {
+                    this._lastNEndpoints = lastNEndpoints;
+                }
+            );
         }
     }
 
     /**
      * Indicates if the endpoint id is currently included in the last N.
      *
-     * @param id the endpoint id that we check for last N
-     * @returns {boolean} {true} if the endpoint id is in the last N or if we
-     * don't have data channel support, otherwise we return {false}
+     * @param {string} id the endpoint id that we check for last N
+     * @returns {boolean} true if the endpoint id is in the last N or if we
+     * don't have data channel support, otherwise we return false
      */
-    isInLastN (id) {
-        return (this.dataChannels) ? this.dataChannels.isInLastN(id) : true;
+    isInLastN(id) {
+        return !this._lastNEndpoints // lastNEndpoints not initialised yet
+            || this._lastNEndpoints.indexOf(id) > -1;
     }
 }

modules/connectivity/ParticipantConnectionStatus.js

             `Figure out conn status, is video muted: ${isVideoMuted
                  } is active(jvb): ${isConnActiveByJvb
                  } video track frozen: ${isVideoTrackFrozen
-                 } is in last N: ${isInLastN}
+                 } is in last N: ${isInLastN
                  } => ${isConnectionActive}`);
 
         this._changeConnectionStatus(participant, isConnectionActive);