[gtk+/gtk-3-22] Avoid a possible crash in ::activate-url handlers

[Matthias Clasen <matthiasc src gnome org>]

commit f19ecbb8503982a00b0f3ee4d5d6c3c73e61deb2
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Dec 29 11:07:05 2016 -0500

    Avoid a possible crash in ::activate-url handlers
    
    If the signal handler ends up changing the label text,
    the link is no longer around to update the css node.
    Check for this possibility to avoid a crash here.

 gtk/gtklabel.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtklabel.c b/gtk/gtklabel.c
index 3affe96..612ad3f 100644
--- a/gtk/gtklabel.c
+++ b/gtk/gtklabel.c
@@ -6739,7 +6739,8 @@ emit_activate_link (GtkLabel     *label,
   GtkStateFlags state;
 
   g_signal_emit (label, signals[ACTIVATE_LINK], 0, link->uri, &handled);
-  if (handled && priv->track_links && !link->visited)
+  if (handled && priv->track_links && !link->visited &&
+      priv->select_info && priv->select_info->links)
     {
       link->visited = TRUE;
       state = gtk_css_node_get_state (link->cssnode);