stylecontext: Make sure style is valid when looking up style properties

Otherwise, the validation may happen vey automatically some time during
the style property and that will most likely cause a crash.

https://bugzilla.gnome.org/show_bug.cgi?id=756338

diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index 0217d55b49c9db7fecaae3e8d2fc7a62a26568b6..5d059a0956ad72e3a0aafec4f6e181213351c15d 100644 (file)
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -1557,6 +1557,9 @@ _gtk_style_context_peek_style_property (GtkStyleContext *context,
 
   priv = context->priv;
 
+  /* ensure the style cache is valid by forcing a validation */
+  gtk_style_context_lookup_style (context);
+
   key.widget_type = widget_type;
   key.pspec = pspec;