ui-frames: Delay attaching the style to new frames

Like the setting of new frames' background is delayed until the
frame is associated with its window, delay attaching the initial
style, so that the correct style variant is picked.

https://bugzilla.gnome.org/show_bug.cgi?id=645355

src/core/frame.c

@@ -154,8 +154,9 @@ meta_window_ensure_frame (MetaWindow *window)
   window->frame = frame;
 
   /* Now that frame->xwindow is registered with window, we can set its
-   * background.
+   * style and background.
    */
+  meta_ui_update_frame_style (window->screen->ui, frame->xwindow);
   meta_ui_reset_frame_bg (window->screen->ui, frame->xwindow);
   
   if (window->title)