[orca] Ignore text-selection-changed events from Gecko objects which have no text

[Joanmarie Diggs <joanied src gnome org>]

commit 8820361476e2735dd3de2d4cd726f0a6d62819b7
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Sun Apr 19 15:35:19 2015 -0400

    Ignore text-selection-changed events from Gecko objects which have no text

 src/orca/scripts/toolkits/Gecko/script.py |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/src/orca/scripts/toolkits/Gecko/script.py b/src/orca/scripts/toolkits/Gecko/script.py
index 758812d..a1523ae 100644
--- a/src/orca/scripts/toolkits/Gecko/script.py
+++ b/src/orca/scripts/toolkits/Gecko/script.py
@@ -1033,6 +1033,11 @@ class Script(default.Script):
             return True
 
         text = self.utilities.queryNonEmptyText(event.source)
+        if not text:
+            msg = "INFO: Text-selection event ignored: There's no text"
+            debug.println(debug.LEVEL_INFO, msg)
+            return
+
         char, start, end = text.getTextAtOffset(text.caretOffset, pyatspi.TEXT_BOUNDARY_CHAR)
         if char == self.EMBEDDED_OBJECT_CHARACTER:
             msg = "INFO: Text-selection event ignored: Caret offset is at embedded object"