[gnome-shell] slider: Do not notify on parent's behalf

[Florian Müllner <fmuellner src gnome org>]

commit f0e1dc5715c2bd9226238c1f35ef916d1006a2c4
Author: Florian Müllner <fmuellner gnome org>
Date:   Mon Aug 12 17:40:54 2019 +0200

    slider: Do not notify on parent's behalf
    
    Instead just use the regular property setter which since commit 3d3dca4aa
    already emits the signal and queues a redraw.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/1500

 js/ui/slider.js | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)
---
diff --git a/js/ui/slider.js b/js/ui/slider.js
index 7672cf67ef..3e35dbcb26 100644
--- a/js/ui/slider.js
+++ b/js/ui/slider.js
@@ -155,10 +155,8 @@ var Slider = GObject.registerClass({
             delta = -dy * SLIDER_SCROLL_STEP;
         }
 
-        this._value = Math.min(Math.max(0, this._value + delta), this._maxValue);
+        this.value = Math.min(Math.max(0, this._value + delta), this._maxValue);
 
-        this.queue_repaint();
-        this.notify('value');
         return Clutter.EVENT_STOP;
     }
 
@@ -177,10 +175,8 @@ var Slider = GObject.registerClass({
         let key = event.get_key_symbol();
         if (key == Clutter.KEY_Right || key == Clutter.KEY_Left) {
             let delta = key == Clutter.KEY_Right ? 0.1 : -0.1;
-            this._value = Math.max(0, Math.min(this._value + delta, this._maxValue));
-            this.queue_repaint();
             this.emit('drag-begin');
-            this.notify('value');
+            this.value = Math.max(0, Math.min(this._value + delta, this._maxValue));
             this.emit('drag-end');
             return Clutter.EVENT_STOP;
         }
@@ -202,9 +198,7 @@ var Slider = GObject.registerClass({
             newvalue = 1;
         else
             newvalue = (relX - handleRadius) / (width - 2 * handleRadius);
-        this._value = newvalue * this._maxValue;
-        this.queue_repaint();
-        this.notify('value');
+        this.value = newvalue * this._maxValue;
     }
 
     _getMinimumIncrement() {