css: Add GtkCssNumber

gtk/gtkcssstylefuncs.c

@@ -1058,6 +1058,13 @@ border_image_repeat_value_print (const GValue *value,
     }
 }
 
+static void
+css_number_print (const GValue *value,
+                  GString      *string)
+{
+  _gtk_css_number_print (g_value_get_boxed (value), string);
+}
+
 static gboolean 
 enum_value_parse (GtkCssParser *parser,
                   GFile        *base,
@@ -1233,6 +1240,10 @@ gtk_css_style_funcs_init (void)
                                 shadow_value_parse,
                                 shadow_value_print,
                                 shadow_value_compute);
+  register_conversion_function (GTK_TYPE_CSS_NUMBER,
+                                NULL,
+                                css_number_print,
+                                NULL);
   register_conversion_function (G_TYPE_ENUM,
                                 enum_value_parse,
                                 enum_value_print,