[orca] Handle another case of objects going defunct on us

[Joanmarie Diggs <joanied src gnome org>]

commit bda902c687baf107429e8470c260a856eac4b0d6
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Mon Mar 30 11:31:00 2020 -0400

    Handle another case of objects going defunct on us

 src/orca/scripts/toolkits/Chromium/script_utilities.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/orca/scripts/toolkits/Chromium/script_utilities.py 
b/src/orca/scripts/toolkits/Chromium/script_utilities.py
index 62dbb8c65..e7e3a364b 100644
--- a/src/orca/scripts/toolkits/Chromium/script_utilities.py
+++ b/src/orca/scripts/toolkits/Chromium/script_utilities.py
@@ -107,7 +107,7 @@ class Utilities(web.Utilities):
             return rv
 
         rv = False
-        if obj.parent.getRole() == pyatspi.ROLE_LIST_ITEM:
+        if obj.parent and obj.parent.getRole() == pyatspi.ROLE_LIST_ITEM:
             rv = self._getTag(obj) in ["::marker", None] and obj.parent[0] == obj
 
         self._isListItemMarker[hash(obj)] = rv