[gnome-shell] background: Don't set background actor sizing and scaling

[Jonas Ådahl <jadahl src gnome org>]

commit 8f1fff137410011cb799541349edf33736e1023f
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Thu Aug 3 15:52:06 2017 +0200

    background: Don't set background actor sizing and scaling
    
    Mutter BackgroundActor is able do detect this at lower level
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765011

 js/ui/background.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
---
diff --git a/js/ui/background.js b/js/ui/background.js
index bcd9ffc13..06e038816 100644
--- a/js/ui/background.js
+++ b/js/ui/background.js
@@ -746,10 +746,8 @@ var BackgroundManager = class BackgroundManager {
 
         this._container.add_child(backgroundActor);
 
-        let monitor = this._layoutManager.monitors[this._monitorIndex];
-
-        backgroundActor.set_size(monitor.width, monitor.height);
         if (this._controlPosition) {
+            let monitor = this._layoutManager.monitors[this._monitorIndex];
             backgroundActor.set_position(monitor.x, monitor.y);
             backgroundActor.lower_bottom();
         }