[orca] Filter out duplicate text when generating real active descendant content

[Joanmarie Diggs <joanied src gnome org>]

commit 5f444e4988b4d34a82b3415bb700fd67d3893ff1
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Thu Oct 18 11:55:51 2018 +0200

    Filter out duplicate text when generating real active descendant content

 src/orca/generator.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/orca/generator.py b/src/orca/generator.py
index 18f04f707..863bc6fda 100644
--- a/src/orca/generator.py
+++ b/src/orca/generator.py
@@ -1115,7 +1115,7 @@ class Generator:
         if not (rad.getRole() == pyatspi.ROLE_TABLE_CELL and rad.childCount):
             return self._generateDisplayedText(rad, **args)
 
-        content = [self._script.utilities.displayedText(x).strip() for x in rad]
+        content = set([self._script.utilities.displayedText(x).strip() for x in rad])
         return [" ".join(filter(lambda x: x, content))]
 
     def _generateRealActiveDescendantRoleName(self, obj, **args ):