barLevel: Use setters instead of methods

Switching to getters/setters make the code suitable for using
with Tweener and as GObject properties, both of which we'll
do soon enough.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/385

js/ui/barLevel.js

@@ -34,7 +34,11 @@ var BarLevel = class {
         this.connect('value-changed', this._valueChanged.bind(this));
     }
 
-    setValue(value) {
+    get value() {
+        return this._value;
+    }
+
+    set value(value) {
         if (isNaN(value))
             throw TypeError('The bar level value must be a number');
 
@@ -42,7 +46,13 @@ var BarLevel = class {
         this.actor.queue_repaint();
     }
 
-    setMaximumValue(value) {
+    // eslint-disable-next-line camelcase
+    get maximum_value() {
+        return this._maxValue;
+    }
+
+    // eslint-disable-next-line camelcase
+    set maximum_value(value) {
         if (isNaN(value))
             throw TypeError('The bar level max value must be a number');
 
@@ -51,7 +61,13 @@ var BarLevel = class {
         this.actor.queue_repaint();
     }
 
-    setOverdriveStart(value) {
+    // eslint-disable-next-line camelcase
+    get overdrive_start() {
+        return this._overdriveStart;
+    }
+
+    // eslint-disable-next-line camelcase
+    set overdrive_start(value) {
         if (isNaN(value))
             throw TypeError('The overdrive limit value must be a number');
         if (value > this._maxValue)
@@ -196,9 +212,5 @@ var BarLevel = class {
     _valueChanged() {
         this._customAccessible.notify("accessible-value");
     }
-
-    get value() {
-        return this._value;
-    }
 };
 Signals.addSignalMethods(BarLevel.prototype);

js/ui/osdWindow.js

@@ -32,7 +32,7 @@ var LevelBar = class extends BarLevel.BarLevel {
     set level(value) {
         this._level = Math.max(0, Math.min(value, this._maxLevel));
 
-        this.setValue(this._level / 100);
+        this.value = this._level / 100;
     }
 
     get maxLevel() {
@@ -42,7 +42,7 @@ var LevelBar = class extends BarLevel.BarLevel {
     set maxLevel(value) {
         this._maxLevel = Math.max(100, value);
 
-        this.setMaximumValue(this._maxLevel / 100);
+        this.maximum_level = this._maxLevel / 100;
     }
 };
 

js/ui/status/brightness.js

@@ -58,6 +58,6 @@ var Indicator = class extends PanelMenu.SystemIndicator {
         let visible = this._proxy.Brightness >= 0;
         this._item.visible = visible;
         if (visible)
-            this._slider.setValue(this._proxy.Brightness / 100.0);
+            this._slider.value = this._proxy.Brightness / 100.0;
     }
 };

js/ui/status/volume.js

@@ -130,17 +130,16 @@ var StreamSlider = class {
 
     _updateVolume() {
         let muted = this._stream.is_muted;
-        this._slider.setValue(muted ? 0 : (this._stream.volume / this._control.get_vol_max_norm()));
+        this._slider.value = muted
+            ? 0 : (this._stream.volume / this._control.get_vol_max_norm());
         this.emit('stream-updated');
     }
 
     _amplifySettingsChanged() {
         this._allowAmplified = this._soundSettings.get_boolean(ALLOW_AMPLIFIED_VOLUME_KEY);
 
-        if (this._allowAmplified)
+        this._slider.maximum_level = this._allowAmplified
-            this._slider.setMaximumValue(this.getMaxLevel() / 100);
+            ? this.getMaxLevel() / 100 : 1;
-        else
-            this._slider.setMaximumValue(1);
 
         if (this._stream)
             this._updateVolume();