[mutter] ui: Fix crash getting default font

[Bastien Nocera <hadess src gnome org>]

commit f1620abfad0caf85b5958e32736accb3fecef7f1
Author: Bastien Nocera <hadess hadess net>
Date:   Fri Mar 29 08:38:46 2013 +0100

    ui: Fix crash getting default font
    
    A correctly constructed GtkStyleContext must have its screen
    and widget paths set. Getting the frame font caused crashes
    on some systems because those were not correctly initialised.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=696814

 src/ui/ui.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/src/ui/ui.c b/src/ui/ui.c
index 2f2fc3a..af28263 100644
--- a/src/ui/ui.c
+++ b/src/ui/ui.c
@@ -744,7 +744,17 @@ meta_ui_theme_get_frame_borders (MetaUI *ui,
 
       if (!font_desc)
         {
+          GdkDisplay *display = gdk_x11_lookup_xdisplay (ui->xdisplay);
+          GdkScreen *screen = gdk_display_get_screen (display, XScreenNumberOfScreen (ui->xscreen));
+          GtkWidgetPath *widget_path;
+
           style = gtk_style_context_new ();
+          gtk_style_context_set_screen (style, screen);
+          widget_path = gtk_widget_path_new ();
+          gtk_widget_path_append_type (widget_path, GTK_TYPE_WINDOW);
+          gtk_style_context_set_path (style, widget_path);
+          gtk_widget_path_free (widget_path);
+
           gtk_style_context_get (style, GTK_STATE_FLAG_NORMAL, "font", &free_font_desc, NULL);
           font_desc = (const PangoFontDescription *) free_font_desc;
         }