Fix logic handling empty strings in tts.

chrome/browser/resources/chromeos/chromevox/host/chrome/tts_background.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview Sends Text-To-Speech commands to Chrome's native TTS
  * extension API.
  *
  */
 
@@ skipping 239 matching lines @@
   textString = this.preprocess(textString, properties);
 
   // TODO(dtseng): Google TTS has bad performance when speaking numbers. This
   // pattern causes ChromeVox to read numbers as digits rather than words.
   textString = this.getNumberAsDigits_(textString);
 
   // TODO(plundblad): Google TTS doesn't handle strings that don't produce
   // any speech very well. Handle empty and whitespace only strings (including
   // non-breaking space) here to mitigate the issue somewhat.
   if (/^[\s\u00a0]*$/.test(textString)) {
+    queueMode = cvox.QueueMode.FLUSH;
+
     // We still want to callback for listeners in our content script.
     if (properties['startCallback']) {
       try {
         properties['startCallback']();
       } catch (e) {
       }
     }
     if (properties['endCallback']) {
       try {
         properties['endCallback']();
       } catch (e) {
       }
     }
-    if (queueMode === cvox.QueueMode.FLUSH) {
-      this.stop();
-    }
     return this;
   }
 
   var mergedProperties = this.mergeProperties(properties);
 
   if (this.currentVoice) {
     mergedProperties['voiceName'] = this.currentVoice;
   }
 
   if (queueMode == cvox.QueueMode.CATEGORY_FLUSH &&
@@ skipping 431 matching lines @@
         voices.find(function(v) { return v.lang === currentLocale; }) ||
         voices.find(function(v) { return currentLocale.startsWith(v.lang); }) ||
         voices[0];
 
     if (newVoice) {
       this.currentVoice = newVoice.voiceName;
       this.startSpeakingNextItemInQueue_();
     }
   }, this));
 };