[gnome-shell] barLevel: Return when trying to set value to already used value

[Florian Müllner <fmuellner src gnome org>]

commit 86c3909908829216767690a4c53699fde25c6c8e
Author: verdre <verdre v0yd nl>
Date:   Sat Feb 2 18:01:56 2019 +0100

    barLevel: Return when trying to set value to already used value
    
    There are some cases (for example when tweening value changes), where
    the level will be set to the same value it already is at. Avoid those
    unnecessary repaints by checking whether the value is already used and
    returning if it is.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/385

 js/ui/barLevel.js | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)
---
diff --git a/js/ui/barLevel.js b/js/ui/barLevel.js
index 78aa03048..ea295f1e8 100644
--- a/js/ui/barLevel.js
+++ b/js/ui/barLevel.js
@@ -42,7 +42,12 @@ var BarLevel = class {
         if (isNaN(value))
             throw TypeError('The bar level value must be a number');
 
-        this._value = Math.max(Math.min(value, this._maxValue), 0);
+        value = Math.max(Math.min(value, this._maxValue), 0);
+
+        if (this._value == value)
+            return;
+
+        this._value = value;
         this.actor.queue_repaint();
     }
 
@@ -56,7 +61,12 @@ var BarLevel = class {
         if (isNaN(value))
             throw TypeError('The bar level max value must be a number');
 
-        this._maxValue = Math.max(value, 1);
+        value = Math.max(value, 1);
+
+        if (this._maxValue == value)
+            return;
+
+        this._maxValue = value;
         this._overdriveStart = Math.min(this._overdriveStart, this._maxValue);
         this.actor.queue_repaint();
     }
@@ -70,6 +80,10 @@ var BarLevel = class {
     set overdrive_start(value) {
         if (isNaN(value))
             throw TypeError('The overdrive limit value must be a number');
+
+        if (this._overdriveStart == value)
+            return;
+
         if (value > this._maxValue)
             throw new Error(`Tried to set overdrive value to ${value}, ` +
                 `which is a number greater than the maximum allowed value ${this._maxValue}`);