[gnome-shell/wip/rstrode/rhel-7.9: 84/86] panel: Handle window getting removed that was never added

[Ray Strode <halfline src gnome org>]

commit 1c8df9122f8b4c58a92463e2b86472d8034c046e
Author: Ray Strode <rstrode redhat com>
Date:   Wed Oct 14 13:51:33 2020 -0400

    panel: Handle window getting removed that was never added
    
    For reasons that are not immediately clear, and actor is getting
    removed that's never been added.  This commit tries to cope
    with that case without making a noise to the log.

 js/ui/panel.js | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
---
diff --git a/js/ui/panel.js b/js/ui/panel.js
index 2ac5886972..74a20cff5f 100644
--- a/js/ui/panel.js
+++ b/js/ui/panel.js
@@ -844,8 +844,13 @@ var Panel = new Lang.Class({
     },
 
     _onWindowActorRemoved(container, metaWindowActor) {
-        this._trackedWindows.get(metaWindowActor).forEach(id => {
-            metaWindowActor.disconnect(id);
+        let signalIds = this._trackedWindows.get(metaWindowActor);
+
+        if (!signalIds)
+            return;
+
+        signalIds.forEach(id => {
+                metaWindowActor.disconnect(id);
         });
         this._trackedWindows.delete(metaWindowActor);
         this._updateSolidStyle();