Fix language switching

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

Index: chrome/browser/resources/chromeos/chromevox/host/chrome/tts_background.js
diff --git a/chrome/browser/resources/chromeos/chromevox/host/chrome/tts_background.js b/chrome/browser/resources/chromeos/chromevox/host/chrome/tts_background.js
index f8bf898a6a625996064ae6425745a58c4af174c9..cf77f90c761957742598b0b02c0c27e674572929 100644
--- a/chrome/browser/resources/chromeos/chromevox/host/chrome/tts_background.js
+++ b/chrome/browser/resources/chromeos/chromevox/host/chrome/tts_background.js
@@ -57,7 +57,7 @@ cvox.TtsBackground = function(opt_enableMath) {
   // specified.
   if (this.ttsProperties['lang'] == undefined) {
     this.ttsProperties['lang'] =
-        chrome.i18n.getMessage('@@ui_locale').replace('_', '-');
+        chrome.i18n.getUILanguage();

[dmazzoni, 2016/11/17 22:49:38]

Did you confirm that this is in the right
format, i.e. with hyphens and not underscores,
and the same capitalization?

[David Tseng, 2016/11/17 23:03:02]

Yes, getMessage seems to be the outlier (xx_XX)

getUILanguage and getAcceptLanguage both return
xx-XX or xx

   }
 
   this.lastEventType = 'end';
@@ -684,20 +684,21 @@ cvox.TtsBackground.prototype.clearTimeout_ = function() {
  */
 cvox.TtsBackground.prototype.updateVoice_ = function(voiceName) {
   chrome.tts.getVoices(goog.bind(function(voices) {
-    var currentLocale = chrome.i18n.getMessage('@@ui_locale').replace('_', '-');
-
-    // 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_();
-    }
+    chrome.i18n.getAcceptLanguages(goog.bind(function(acceptLanguages) {
+      var currentLocale = acceptLanguages[0] ||

[dmazzoni, 2016/11/17 22:49:38]

Ideally we should use all acceptLanguages?
Maybe add a TODO

[David Tseng, 2016/11/17 23:03:02]

It's all kind of guess work at this point because I see the browser UI language
is different from the user's accept language and ChromeVox localized strings are
all based upon the ui locale (i.e. the extension resources).

We should definitely re-visit. Note the prsence of
chrome.i18n.detectLanguage
which we could use on a page to figure out which tts voice to use. I tried it
out and our engine is just too slow in switching to make it practical (not to
even begin considering how reliable the detection is).

+          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.startsWith(currentLocale); }) ||
+          voices[0];
+
+      if (newVoice) {
+        this.currentVoice = newVoice.voiceName;
+        this.startSpeakingNextItemInQueue_();
+      }
+    }, this));
   }, this));
 };