Workaround for Chrome ice connection failure detection (#1685)

* fix: re-enable that ICE connection failures in Chrome are detected
* fixed linting errors

modules/RTC/TraceablePeerConnection.js

             this.onnegotiationneeded(event);
         }
     };
+    this.onconnectionstatechange = null;
+    this.peerconnection.onconnectionstatechange = event => {
+        this.trace('onconnectionstatechange', this.connectionState);
+        if (this.onconnectionstatechange !== null) {
+            this.onconnectionstatechange(event);
+        }
+    };
     this.ondatachannel = null;
     this.peerconnection.ondatachannel = event => {
         this.trace('ondatachannel');
     iceConnectionState() {
         return this.peerconnection.iceConnectionState;
     },
+    connectionState() {
+        return this.peerconnection.connectionState;
+    },
     localDescription() {
         let desc = this.peerconnection.localDescription;
 

modules/xmpp/JingleSessionPC.js

             }
         };
 
+
+        /**
+         * The connection state event is fired whenever the aggregate of underlying
+         * transports change their state.
+         */
+        this.peerconnection.onconnectionstatechange = () => {
+            const icestate = this.peerconnection.iceConnectionState;
+
+            switch (this.peerconnection.connectionState) {
+            case 'failed':
+                // Since version 76 Chrome no longer switches ICE connection
+                // state to failed (see
+                // https://bugs.chromium.org/p/chromium/issues/detail?id=982793
+                // for details) we use this workaround to recover from lost connections
+                if (icestate === 'disconnected') {
+                    this.room.eventEmitter.emit(
+                        XMPPEvents.CONNECTION_ICE_FAILED, this);
+                }
+                break;
+            }
+        };
+
         /**
          * The negotiationneeded event is fired whenever we shake the media on the
          * RTCPeerConnection object.