[orca] Fall back on event source when getting page summary for null caret context

[Joanmarie Diggs <joanied src gnome org>]

commit 59928b1543bd39b3639f6b8674973a88e4d6a626
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Tue Oct 16 14:16:30 2018 +0200

    Fall back on event source when getting page summary for null caret context

 src/orca/scripts/web/script.py | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/orca/scripts/web/script.py b/src/orca/scripts/web/script.py
index 7ca5abba1..4deefa9d4 100644
--- a/src/orca/scripts/web/script.py
+++ b/src/orca/scripts/web/script.py
@@ -1269,6 +1269,7 @@ class Script(default.Script):
         self.utilities.clearCachedObjects()
 
         if _settingsManager.getSetting('pageSummaryOnLoad') and shouldPresent:
+            obj = obj or event.source
             msg = "WEB: Getting page summary for obj %s" % obj
             debug.println(debug.LEVEL_INFO, msg, True)
             summary = self.utilities.getPageSummary(obj)