animation: Add (integer) geometry scaling support to Spinner

Until now it only supported (float) fractional scaling.

Since the SpinnerContent requires a Clutter size in logical pixels,
we need to specify that at map time when the scaling factor is known.

Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/8126
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3634>

js/ui/animation.js

@@ -15,16 +15,22 @@ class Spinner extends St.Widget {
             hideOnStop: false,
         });
         super({
-            width: size,
-            height: size,
             opacity: 0,
         });
 
+        this._size = size;
         this._animate = params.animate;
         this._hideOnStop = params.hideOnStop;
         this.visible = !this._hideOnStop;
     }
 
+    vfunc_map() {
+        const {scaleFactor} = St.ThemeContext.get_for_stage(global.stage);
+        const logicalSize = this._size * scaleFactor;
+        this.set_size(logicalSize, logicalSize);
+        super.vfunc_map();
+    }
+
     play() {
         this.remove_all_transitions();
         this.set_content(new St.SpinnerContent());