[gtk+/gtk-2-24-quartz] Fix a segfault if the GAppInfo does not have an icon

[John Ralls <jralls src gnome org>]

commit bb1291718c3c1e2dd615cf757f4206640aa87c27
Author: Richard Hughes <richard hughsie com>
Date:   Tue Sep 13 16:16:28 2011 +0100

    Fix a segfault if the GAppInfo does not have an icon
    
    This fixes the following backtrace:
    
     0  g_logv (log_domain=0x7ffff60461a4 "GLib-GObject", log_level=<optimized out>,
        format=0x7ffff599c322 "%s: assertion `%s' failed", args1=0x7fffffffc418) at gmessages.c:577
     1  0x00007ffff59312d2 in g_log (log_domain=<optimized out>, log_level=<optimized out>,
        format=<optimized out>) at gmessages.c:591
     2  0x00007ffff601c3c7 in g_object_ref (_object=0x0) at gobject.c:2648
     3  0x00007ffff7721e22 in gdk_x11_app_launch_context_get_startup_notify_id (context=<optimized out>,
        info=0x7fffe8004b40, files=<optimized out>) at gdkapplaunchcontext-x11.c:331
     4  0x00007ffff62e60d0 in _g_desktop_app_info_launch_uris_internal (appinfo=0x7fffe8004b40, uris=0x0,
        launch_context=0x7fffe401c800, spawn_flags=G_SPAWN_SEARCH_PATH, user_setup=0, user_setup_data=0x0,
        pid_callback=0, pid_callback_data=0x0, error=0x7fffffffc848) at gdesktopappinfo.c:1269
     5  0x00007ffff62e630a in g_desktop_app_info_launch_uris (appinfo=<optimized out>, uris=<optimized out>,
        launch_context=<optimized out>, error=<optimized out>) at gdesktopappinfo.c:1341
     6  0x00007ffff62e636b in g_desktop_app_info_launch (appinfo=0x7fffe8004b40, files=<optimized out>,
        launch_context=0x7fffe401c800, error=0x7fffffffc848) at gdesktopappinfo.c:1388

 gdk/x11/gdkapplaunchcontext-x11.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)
---
diff --git a/gdk/x11/gdkapplaunchcontext-x11.c b/gdk/x11/gdkapplaunchcontext-x11.c
index 20db4ab..8796cc3 100644
--- a/gdk/x11/gdkapplaunchcontext-x11.c
+++ b/gdk/x11/gdkapplaunchcontext-x11.c
@@ -340,13 +340,15 @@ _gdk_windowing_get_startup_notify_id (GAppLaunchContext *context,
       if (icon == NULL)
         {
           icon = g_app_info_get_icon (info);
-          g_object_ref (icon);
+          if (icon != NULL)
+            g_object_ref (icon);
         }
 
-      if (icon)
-        icon_name = gicon_to_string (icon);
-
-      g_object_unref (icon);
+      if (icon != NULL)
+        {
+          icon_name = gicon_to_string (icon);
+          g_object_unref (icon);
+        }
     }
 
   binary_name = g_app_info_get_executable (info);