Fix language switching

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 39 matching lines @@
       this.propertyDefault['rate']);
   this.ttsProperties['pitch'] = (parseFloat(localStorage['pitch']) ||
       this.propertyDefault['pitch']);
   this.ttsProperties['volume'] = (parseFloat(localStorage['volume']) ||
       this.propertyDefault['volume']);
 
   // Use the current locale as the speech language if not otherwise
   // specified.
   if (this.ttsProperties['lang'] == undefined) {
     this.ttsProperties['lang'] =
-        chrome.i18n.getMessage('@@ui_locale').replace('_', '-');
+        chrome.i18n.getUILanguage();
   }
 
   this.lastEventType = 'end';
 
   /** @private {number} */
   this.currentPunctuationEcho_ =
       parseInt(localStorage[cvox.AbstractTts.PUNCTUATION_ECHO] || 1, 10);
 
   /**
    * @type {!Array<{name:(string),
@@ skipping 602 matching lines @@
     clearTimeout(this.timeoutId_);
     this.timeoutId_ = undefined;
   }
 };
 
 
 /**
  * Update the current voice used to speak based upon values in storage. If that
  * does not succeed, fallback to use system locale when picking a voice.
  * @param {string} voiceName Voice name to set.
+ * @param {function(string) : void=} opt_callback Called when the voice is
+ * determined.
  * @private
  */
-cvox.TtsBackground.prototype.updateVoice_ = function(voiceName) {
+cvox.TtsBackground.prototype.updateVoice_ = function(voiceName, opt_callback) {
   chrome.tts.getVoices(goog.bind(function(voices) {
-    var currentLocale = chrome.i18n.getMessage('@@ui_locale').replace('_', '-');
+    chrome.i18n.getAcceptLanguages(goog.bind(function(acceptLanguages) {
+      var currentLocale = acceptLanguages[0] ||
+          chrome.i18n.getUILanguage() || '';
+      var match = voices.find.bind(voices);
+      var newVoice =
+          match(function(v) { return v.voiceName == voiceName; }) ||
+          match(function(v) { return v.lang === currentLocale; }) ||
+          match(function(v) { return currentLocale.startsWith(v.lang); }) ||
+          match(function(v) { return v.lang &&
+              v.lang.startsWith(currentLocale); }) ||
+          voices[0];
 
-    // TODO(dtseng): Prefer voices having the default property once we switch to
-    // web speech. See crbug.com/544139.
-
-    var newVoice = voices.find(
-            function(v) { return v.voiceName == voiceName; }) ||
-        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_();
-    }
+      if (newVoice) {
+        this.currentVoice = newVoice.voiceName;
+        this.startSpeakingNextItemInQueue_();
+      }
+      if (opt_callback)
+        opt_callback(this.currentVoice);
+    }, this));
   }, this));
 };