[gtk+] cssvalue: Handle named colors not resolving

[Benjamin Otte <otte src gnome org>]

commit c25d8e3aea900f8ae2abd2907a5b8a2e89e7ee9e
Author: Benjamin Otte <otte redhat com>
Date:   Thu Mar 28 22:52:30 2013 +0100

    cssvalue: Handle named colors not resolving
    
    If a named color references a nonexistant named color, we didn't catch
    that error and ended up crashing on a NULL-dereference.
    This crashed Boxes, because its CSS referenced values from the theme
    that didn't exist in any theme.

 gtk/gtkcsscolorvalue.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcsscolorvalue.c b/gtk/gtkcsscolorvalue.c
index 9ff0a05..64933bd 100644
--- a/gtk/gtkcsscolorvalue.c
+++ b/gtk/gtkcsscolorvalue.c
@@ -166,6 +166,8 @@ _gtk_css_color_value_resolve (GtkCssValue             *color,
          return NULL;
 
         value = _gtk_css_color_value_resolve (named, provider, current, current_deps, dependencies);
+       if (value == NULL)
+         return NULL;
       }
 
       break;