[mutter] window: Treat being headless as not monitor sized

[Jonas Ådahl <jadahl src gnome org>]

commit 39aae19ed7e71fbe01bbb445504d580b13b0c12e
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Sep 25 14:09:31 2017 -0400

    window: Treat being headless as not monitor sized
    
    When we are headless, treat this as if the window is always not monitor
    sized. This might cause windows to temporarly become redirected while
    being headless, but this is harmless as when a new monitor is
    connected, we'll recalculate weather it should be redirected or not.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=787637

 src/core/window.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/core/window.c b/src/core/window.c
index d450a5c..d3c0fa5 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -2904,6 +2904,9 @@ meta_window_is_screen_sized (MetaWindow *window)
 gboolean
 meta_window_is_monitor_sized (MetaWindow *window)
 {
+  if (!window->monitor)
+    return FALSE;
+
   if (window->fullscreen)
     return TRUE;