[gtk+] gtkapplication: g_dbus_proxy_new_sync can return NULL

[Matthias Clasen <matthiasc src gnome org>]

commit edf0aeb92e5bdcde834a40698a87b1e74d424fda
Author: Timm Bäder <mail baedert org>
Date:   Sun Jul 9 10:02:34 2017 +0200

    gtkapplication: g_dbus_proxy_new_sync can return NULL
    
    Specifically, in the case where @error is set.

 gtk/gtkapplication-dbus.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkapplication-dbus.c b/gtk/gtkapplication-dbus.c
index 3ad964e..be88565 100644
--- a/gtk/gtkapplication-dbus.c
+++ b/gtk/gtkapplication-dbus.c
@@ -131,6 +131,9 @@ gtk_application_get_proxy_if_service_present (GDBusConnection *connection,
                                  NULL,
                                  error);
 
+  if (!proxy)
+    return NULL;
+
   /* is there anyone actually providing the service? */
   owner = g_dbus_proxy_get_name_owner (proxy);
   if (owner == NULL)