[orca] Filter out empty lists when generating contents

[Joanmarie Diggs <joanied src gnome org>]

commit 08bdd292cda6f0b9ff7b75765d32ca6cdcfa88c7
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Fri Jul 6 08:57:46 2018 -0400

    Filter out empty lists when generating contents

 src/orca/scripts/web/speech_generator.py | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/orca/scripts/web/speech_generator.py b/src/orca/scripts/web/speech_generator.py
index 457d58429..8ea30e22d 100644
--- a/src/orca/scripts/web/speech_generator.py
+++ b/src/orca/scripts/web/speech_generator.py
@@ -540,6 +540,9 @@ class SpeechGenerator(speech_generator.SpeechGenerator):
             utterance = self.generateSpeech(
                 obj, startOffset=start, endOffset=end, string=string,
                 index=i, total=len(contents), **args)
+            if isinstance(utterance, list):
+                isNotEmptyList = lambda x: not (isinstance(x, list) and not x)
+                utterance = list(filter(isNotEmptyList, utterance))
             if utterance and utterance[0]:
                 result.append(utterance)
                 args['priorObj'] = obj