[libchamplain] champlain-view: Remove children from user_layers in dispose

[Jiří Techet <jiritechet src gnome org>]

commit 5038ab1b704e609ba76958075a4b61eab13699b0
Author: Jonas Danielsson <jonas threetimestwo org>
Date:   Tue Feb 16 10:54:00 2016 +0100

    champlain-view: Remove children from user_layers in dispose
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760012

 champlain/champlain-view.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/champlain/champlain-view.c b/champlain/champlain-view.c
index bf53868..97d2f01 100644
--- a/champlain/champlain-view.c
+++ b/champlain/champlain-view.c
@@ -726,6 +726,10 @@ champlain_view_dispose (GObject *object)
 
   priv->map_layer = NULL;
   priv->license_actor = NULL;
+
+  /* This is needed to prevent race condition see bug #760012 */
+  if (priv->user_layers)
+      clutter_actor_remove_all_children (priv->user_layers);
   priv->user_layers = NULL;
   priv->zoom_layer = NULL;