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/pointerWatcher.js

@@ -1,7 +1,6 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 
 const GLib = imports.gi.GLib;
-const Lang = imports.lang;
 const Mainloop = imports.mainloop;
 const Meta = imports.gi.Meta;
 const GnomeDesktop = imports.gi.GnomeDesktop;
@@ -22,14 +21,12 @@ function getPointerWatcher() {
     return _pointerWatcher;
 }
 
-var PointerWatch = new Lang.Class({
-    Name: 'PointerWatch',
-
-    _init(watcher, interval, callback) {
+var PointerWatch = class {
+    constructor(watcher, interval, callback) {
         this.watcher = watcher;
         this.interval = interval;
         this.callback = callback;
-    },
+    }
 
     // remove:
     // remove this watch. This function may safely be called
@@ -37,19 +34,17 @@ var PointerWatch = new Lang.Class({
     remove() {
         this.watcher._removeWatch(this);
     }
-});
+};
 
-var PointerWatcher = new Lang.Class({
-    Name: 'PointerWatcher',
-
-    _init() {
+var PointerWatcher = class {
+    constructor() {
         this._idleMonitor = Meta.IdleMonitor.get_core();
         this._idleMonitor.add_idle_watch(IDLE_TIME, this._onIdleMonitorBecameIdle.bind(this));
         this._idle = this._idleMonitor.get_idletime() > IDLE_TIME;
         this._watches = [];
         this.pointerX = null;
         this.pointerY = null;
-    },
+    }
 
     // addWatch:
     // @interval: hint as to the time resolution needed. When the user is
@@ -68,7 +63,7 @@ var PointerWatcher = new Lang.Class({
         this._watches.push(watch);
         this._updateTimeout();
         return watch;
-    },
+    }
 
     _removeWatch(watch) {
         for (let i = 0; i < this._watches.length; i++) {
@@ -78,19 +73,19 @@ var PointerWatcher = new Lang.Class({
                 return;
             }
         }
-    },
+    }
 
     _onIdleMonitorBecameActive(monitor) {
         this._idle = false;
         this._updatePointer();
         this._updateTimeout();
-    },
+    }
 
     _onIdleMonitorBecameIdle(monitor) {
         this._idle = true;
         this._idleMonitor.add_user_active_watch(this._onIdleMonitorBecameActive.bind(this));
         this._updateTimeout();
-    },
+    }
 
     _updateTimeout() {
         if (this._timeoutId) {
@@ -108,12 +103,12 @@ var PointerWatcher = new Lang.Class({
         this._timeoutId = Mainloop.timeout_add(minInterval,
                                                this._onTimeout.bind(this));
         GLib.Source.set_name_by_id(this._timeoutId, '[gnome-shell] this._onTimeout');
-    },
+    }
 
     _onTimeout() {
         this._updatePointer();
         return GLib.SOURCE_CONTINUE;
-    },
+    }
 
     _updatePointer() {
         let [x, y, mods] = global.get_pointer();
@@ -130,4 +125,4 @@ var PointerWatcher = new Lang.Class({
                 i++;
         }
     }
-});
+};