[gnome-shell] workspaceSwitcherPopup: Set offscreen redirect always

[Florian Müllner <fmuellner src gnome org>]

commit 9363fd35243ee2fe502725951389d2bbc18483a9
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Wed Jul 8 18:06:39 2020 +0800

    workspaceSwitcherPopup: Set offscreen redirect always
    
    Because for most frames during a workspace switch it's not changing and
    we can repaint it faster if it's cached on the GPU as a single texture.
    
    This seems to reduce the render time for workspace switching by more
    than 20%.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1356

 js/ui/workspaceSwitcherPopup.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/workspaceSwitcherPopup.js b/js/ui/workspaceSwitcherPopup.js
index eebf9db3b7..4613e96ecf 100644
--- a/js/ui/workspaceSwitcherPopup.js
+++ b/js/ui/workspaceSwitcherPopup.js
@@ -11,7 +11,10 @@ var DISPLAY_TIMEOUT = 600;
 var WorkspaceSwitcherPopupList = GObject.registerClass(
 class WorkspaceSwitcherPopupList extends St.Widget {
     _init() {
-        super._init({ style_class: 'workspace-switcher' });
+        super._init({
+            style_class: 'workspace-switcher',
+            offscreen_redirect: Clutter.OffscreenRedirect.ALWAYS,
+        });
 
         this._itemSpacing = 0;
         this._childHeight = 0;