style(JitsiLocalTrack):Rename method & add comment

modules/RTC/JitsiLocalTrack.js

@@ -147,7 +147,7 @@ export default class JitsiLocalTrack extends JitsiTrack {
          */
         this._noDataFromSourceTimeout = null;
 
-        this._onDeviceListChanged = devices => {
+        this._onDeviceListWillChange = devices => {
             this._setRealDeviceIdFromDeviceList(devices);
 
             // Mark track as ended for those browsers that do not support
@@ -171,7 +171,7 @@ export default class JitsiLocalTrack extends JitsiTrack {
                 this._onAudioOutputDeviceChanged);
         }
 
-        RTCUtils.addListener(RTCEvents.DEVICE_LIST_WILL_CHANGE, this._onDeviceListChanged);
+        RTCUtils.addListener(RTCEvents.DEVICE_LIST_WILL_CHANGE, this._onDeviceListWillChange);
 
         this._initNoDataFromSourceHandlers();
     }
@@ -269,6 +269,9 @@ export default class JitsiLocalTrack extends JitsiTrack {
         let device = devices.find(d => d.kind === kind && d.label === track.label);
 
         if (!device && this._realDeviceId === 'default') { // the default device has been changed.
+            // If the default device was 'A' and the default device is changed to 'B' the label for the track will
+            // remain 'Default - A' but the label for the device in the device list will be updated to 'A'. That's
+            // why in order to match it we need to remove the 'Default - ' part.
             const label = (track.label || '').replace('Default - ', '');
 
             device = devices.find(d => d.kind === kind && d.label === label);
@@ -525,7 +528,7 @@ export default class JitsiLocalTrack extends JitsiTrack {
             this.detach();
         }
 
-        RTCUtils.removeListener(RTCEvents.DEVICE_LIST_WILL_CHANGE, this._onDeviceListChanged);
+        RTCUtils.removeListener(RTCEvents.DEVICE_LIST_WILL_CHANGE, this._onDeviceListWillChange);
 
         if (this._onAudioOutputDeviceChanged) {
             RTCUtils.removeListener(RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED,