Cherry-pick 3c7d5e7 to fix a critical on gtk_application_shutdown

When not using portals

Closes: #908070

debian/patches/GtkApplication-Fix-CRITICAL-on-shutdown-when-register_ses.patch

@@ -0,0 +1,46 @@
+From: "Jan Alexander Steffens (heftig)" <jan.steffens@gmail.com>
+Date: Wed, 5 Sep 2018 21:46:28 +0200
+Subject: GtkApplication: Fix CRITICAL on shutdown when register_session=FALSE
+
+Origin: upstream, commit:3c7d5e749ccafa75718ef00f1d5f6cdc0defacb3
+Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=908070
+---
+ gtk/gtkapplication-dbus.c | 25 ++++++++++++++++---------
+ 1 file changed, 16 insertions(+), 9 deletions(-)
+
+diff --git a/gtk/gtkapplication-dbus.c b/gtk/gtkapplication-dbus.c
+index 25015eb..0946edf 100644
+--- a/gtk/gtkapplication-dbus.c
++++ b/gtk/gtkapplication-dbus.c
+@@ -826,15 +826,22 @@ gtk_application_impl_dbus_finalize (GObject *object)
+ {
+   GtkApplicationImplDBus *dbus = (GtkApplicationImplDBus *) object;
+ 
+-  g_dbus_connection_call (dbus->session,
+-                          "org.freedesktop.portal.Desktop",
+-                          dbus->session_id,
+-                          "org.freedesktop.portal.Session",
+-                          "Close",
+-                          NULL, NULL, 0, -1, NULL, NULL, NULL);
+-
+-  g_free (dbus->session_id);
+-  g_dbus_connection_signal_unsubscribe (dbus->session, dbus->state_changed_handler);
++  if (dbus->session_id)
++    {
++      g_dbus_connection_call (dbus->session,
++                              "org.freedesktop.portal.Desktop",
++                              dbus->session_id,
++                              "org.freedesktop.portal.Session",
++                              "Close",
++                              NULL, NULL, 0, -1, NULL, NULL, NULL);
++
++      g_free (dbus->session_id);
++    }
++
++  if (dbus->state_changed_handler)
++    g_dbus_connection_signal_unsubscribe (dbus->session,
++                                          dbus->state_changed_handler);
++
+   g_clear_object (&dbus->inhibit_proxy);
+   g_slist_free_full (dbus->inhibit_handles, inhibit_handle_free);
+   g_free (dbus->app_menu_path);

debian/patches/series

@@ -1,3 +1,4 @@
+GtkApplication-Fix-CRITICAL-on-shutdown-when-register_ses.patch
 016_no_offscreen_widgets_grabbing.patch
 017_no_offscreen_device_grabbing.patch
 018_gdkenumtypes.c_location.patch