[epiphany] embed-shell: fix criticals in delayed_thumbnail_update_data_free

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 368e486c175840de3eb687a4f9d7dad063d78bc2
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Mon Feb 13 22:51:34 2017 -0600

    embed-shell: fix criticals in delayed_thumbnail_update_data_free

 embed/ephy-embed-shell.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/embed/ephy-embed-shell.c b/embed/ephy-embed-shell.c
index 258c053..1c0195f 100644
--- a/embed/ephy-embed-shell.c
+++ b/embed/ephy-embed-shell.c
@@ -378,7 +378,8 @@ delayed_thumbnail_update_data_new (EphyWebExtensionProxy *extension,
 static void
 delayed_thumbnail_update_data_free (DelayedThumbnailUpdateData *data)
 {
-  g_object_remove_weak_pointer (G_OBJECT (data->extension), (gpointer *)&data->extension);
+  if (data->extension)
+    g_object_remove_weak_pointer (G_OBJECT (data->extension), (gpointer *)&data->extension);
   g_free (data->url);
   g_free (data->path);
   g_free (data);