[gnome-break-timer] Log a warning if Mutter idle monitor disappears

[Dylan McCall <dylanmccall src gnome org>]

commit 2116389abb38b4b085afca498327fa0d8878b69d
Author: Dylan McCall <dylan dylanmccall ca>
Date:   Sun Nov 22 23:58:10 2020 -0800

    Log a warning if Mutter idle monitor disappears
    
    There may be an issue related to this.

 src/daemon/activity/MutterActivityMonitorBackend.vala | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/daemon/activity/MutterActivityMonitorBackend.vala 
b/src/daemon/activity/MutterActivityMonitorBackend.vala
index 2a12e74..ac169ad 100644
--- a/src/daemon/activity/MutterActivityMonitorBackend.vala
+++ b/src/daemon/activity/MutterActivityMonitorBackend.vala
@@ -75,6 +75,7 @@ public class MutterActivityMonitorBackend : ActivityMonitorBackend, GLib.Initabl
     }
 
     private void mutter_idle_monitor_disappeared () {
+        GLib.warning ("Mutter idle monitor disappeared")
         this.mutter_idle_monitor = null;
         this.idle_watch_id = 0;
     }