[gnome-shell] altTab: Ensure style of this._list before calculating icon sizes

[Florian Müllner <fmuellner src gnome org>]

commit eab320dab59e702cda3d2864be2bb59c03d34d79
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Thu Jun 20 23:01:52 2019 +0200

    altTab: Ensure style of this._list before calculating icon sizes
    
    We're calculating icon sizes for the alt tab switcher early and at a
    point where the style attributes of this._list are not loaded yet. To
    make sure the value of this._list.spacing is correct, call
    ensure_style() on this._list before accessing the spacing.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/587

 js/ui/altTab.js | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/js/ui/altTab.js b/js/ui/altTab.js
index ae9846552..6c9aaf1c1 100644
--- a/js/ui/altTab.js
+++ b/js/ui/altTab.js
@@ -728,6 +728,7 @@ class AppSwitcher extends SwitcherPopup.SwitcherList {
                 j++;
         }
         let themeNode = this._items[j].get_theme_node();
+        this._list.ensure_style();
 
         let iconPadding = themeNode.get_horizontal_padding();
         let iconBorder = themeNode.get_border_width(St.Side.LEFT) + 
themeNode.get_border_width(St.Side.RIGHT);