workspace: Ensure style of window-chrome titles before requesting width

Make sure the stylesheet properties of the window-chrome title are
updated before requesting the preferred width of the title to prevent
size changes of the title after we animated the width.

Fixes https://gitlab.gnome.org/GNOME/gnome-shell/issues/58

js/ui/workspace.js

@@ -578,6 +578,8 @@ var WindowOverlay = class {
         border.remove_all_transitions();
         title.remove_all_transitions();
 
+        title.ensure_style();
+
         let [cloneX, cloneY, cloneWidth, cloneHeight] = this._windowClone.slot;
 
         let layout = Meta.prefs_get_button_layout();