cleanup: Use arrow notation for anonymous functions

Arrow notation is great, use it consistently through-out the code base
to bind `this` to anonymous functions, replacing the more overbose
Lang.bind(this, function() {}).

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/23

js/ui/grabHelper.js

@@ -67,7 +67,9 @@ var GrabHelper = new Lang.Class({
     // Adds @actor to the set of actors that are allowed to process events
     // during a grab.
     addActor(actor) {
-        actor.__grabHelperDestroyId = actor.connect('destroy', Lang.bind(this, function() { this.removeActor(actor); }));
+        actor.__grabHelperDestroyId = actor.connect('destroy', () => {
+            this.removeActor(actor);
+        });
         this._actors.push(actor);
     },