[gtk/wip/chergert/fix-flowboxchild-crash-on-selection] flowbox: check for flowbox when updating selection

[Christian Hergert <chergert src gnome org>]

commit 8dfb33fb5f314741bd0efea4626b93edcf9df7d7
Author: Christian Hergert <chergert redhat com>
Date:   Fri Mar 29 16:26:20 2019 -0700

    flowbox: check for flowbox when updating selection

 gtk/gtkflowbox.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gtk/gtkflowbox.c b/gtk/gtkflowbox.c
index 0a02376bb9..e5414d4c2e 100644
--- a/gtk/gtkflowbox.c
+++ b/gtk/gtkflowbox.c
@@ -297,6 +297,9 @@ gtk_flow_box_child_set_focus (GtkFlowBoxChild *child)
   gboolean modify;
   gboolean extend;
 
+  if (box == NULL)
+    return;
+
   get_current_selection_modifiers (GTK_WIDGET (box), &modify, &extend);
 
   if (modify)