[orca] Treat gnome-shell selection changes like focus changes for script activation

[Joanmarie Diggs <joanied src gnome org>]

commit e230e807da4d58b261437a4c24091e7779e13709
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Mon Mar 26 14:43:12 2018 -0400

    Treat gnome-shell selection changes like focus changes for script activation

 src/orca/scripts/apps/gnome-shell/script.py |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/src/orca/scripts/apps/gnome-shell/script.py b/src/orca/scripts/apps/gnome-shell/script.py
index dbabd9f..eadfb1f 100644
--- a/src/orca/scripts/apps/gnome-shell/script.py
+++ b/src/orca/scripts/apps/gnome-shell/script.py
@@ -210,3 +210,9 @@ class Script(clutter.Script):
             return False
 
         return super().echoPreviousWord(obj, offset)
+
+    def isActivatableEvent(self, event):
+        if event.type.startswith('object:state-changed:selected') and event.detail1:
+            return True
+
+        return super().isActivatableEvent(event)