cleanup: Port non-GObject classes to JS6 classes

ES6 finally adds standard class syntax to the language, so we can
replace our custom Lang.Class framework with the new syntax. Any
classes that inherit from GObject will need special treatment,
so limit the port to regular javascript classes for now.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/361

js/ui/status/remoteAccess.js

@@ -1,17 +1,13 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 
-const Lang = imports.lang;
 const Meta = imports.gi.Meta;
 
 const PanelMenu = imports.ui.panelMenu;
 const PopupMenu = imports.ui.popupMenu;
 
-var RemoteAccessApplet = new Lang.Class({
-    Name: 'RemoteAccessApplet',
-    Extends: PanelMenu.SystemIndicator,
-
-    _init() {
-        this.parent();
+var RemoteAccessApplet = class extends PanelMenu.SystemIndicator {
+    constructor() {
+        super();
 
         let backend = Meta.get_backend();
         let controller = backend.get_remote_access_controller();
@@ -33,7 +29,7 @@ var RemoteAccessApplet = new Lang.Class({
         controller.connect('new-handle', (controller, handle) => {
             this._onNewHandle(handle);
         });
-    },
+    }
 
     _ensureControls() {
         if (this._indicator)
@@ -52,7 +48,7 @@ var RemoteAccessApplet = new Lang.Class({
                                   });
         this._item.icon.icon_name = 'screen-shared-symbolic';
         this.menu.addMenuItem(this._item);
-    },
+    }
 
     _sync() {
         if (this._handles.size == 0) {
@@ -62,12 +58,12 @@ var RemoteAccessApplet = new Lang.Class({
             this._indicator.visible = true;
             this._item.actor.visible = true;
         }
-    },
+    }
 
     _onStopped(handle) {
         this._handles.delete(handle);
         this._sync();
-    },
+    }
 
     _onNewHandle(handle) {
         this._handles.add(handle);
@@ -77,5 +73,5 @@ var RemoteAccessApplet = new Lang.Class({
             this._ensureControls();
             this._sync();
         }
-    },
-});
+    }
+};