pointerA11yTimeout: Draw a clean circle if the pie is finished

If the circle is complete and the pie timeout finished, we don't need
the lines to the center point indicating the ends of the pie anymore.
We just draw a clean circle instead, which allows for a zoom-out and
fade animation of the circle when we're done.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/688

js/ui/pointerA11yTimeout.js

@@ -50,9 +50,14 @@ var PieTimer = GObject.registerClass({
         cr.setLineJoin(Cairo.LineJoin.ROUND);
         cr.translate(width / 2, height / 2);
 
+        if (this._angle < 2 * Math.PI)
             cr.moveTo(0, 0);
+
         cr.arc(0, 0, radius - borderWidth, startAngle, endAngle);
+
+        if (this._angle < 2 * Math.PI)
             cr.lineTo(0, 0);
+
         cr.closePath();
 
         cr.setLineWidth(0);