ChromeVox: Fix 'No voice for <language>' message upon startup.

(repros 0/10 times).
was available for system language (at startup).

Bug: 1086640
Test: Manually verify by running ChromeVox startup 10 times
Change-Id: I8c735a58e6c943916792430bb96e6b2ccf3eeb88
AX-Relnotes: Fix voice switching issue where ChromeVox said no voice
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2216379
Commit-Queue: Akihiro Ota <akihiroota@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772713}

chrome/browser/resources/chromeos/accessibility/chromevox/background/background.js

@@ -15,32 +15,34 @@ goog.require('BackgroundKeyboardHandler');
 goog.require('BackgroundMouseHandler');
 goog.require('BrailleCommandData');
 goog.require('BrailleCommandHandler');
+goog.require('BrailleKeyCommand');
+goog.require('ChromeVoxBackground');
+goog.require('ChromeVoxEditableTextBase');
 goog.require('ChromeVoxState');
 goog.require('CommandHandler');
 goog.require('DesktopAutomationHandler');
 goog.require('DownloadHandler');
+goog.require('ExtensionBridge');
 goog.require('FindHandler');
+goog.require('FocusAutomationHandler');
 goog.require('GestureCommandHandler');
 goog.require('LiveRegions');
+goog.require('LocaleOutputHelper');
 goog.require('MathHandler');
 goog.require('MediaAutomationHandler');
+goog.require('NavBraille');
 goog.require('NextEarcons');
+goog.require('NodeIdentifier');
 goog.require('Notifications');
 goog.require('Output');
 goog.require('Output.EventType');
 goog.require('PanelCommand');
 goog.require('PhoneticData');
-goog.require('FocusAutomationHandler');
 goog.require('RangeAutomationHandler');
+goog.require('UserAnnotationHandler');
 goog.require('constants');
 goog.require('cursors.Cursor');
-goog.require('BrailleKeyCommand');
-goog.require('ChromeVoxBackground');
-goog.require('ChromeVoxEditableTextBase');
-goog.require('ExtensionBridge');
-goog.require('NavBraille');
-goog.require('NodeIdentifier');
-goog.require('UserAnnotationHandler');
+
 
 goog.scope(function() {
 const AutomationNode = chrome.automation.AutomationNode;
@@ -58,6 +60,7 @@ Background = class extends ChromeVoxState {
 
     // Initialize legacy background page first.
     ChromeVoxBackground.init();
+    LocaleOutputHelper.init();
 
     /**
      * A list of site substring patterns to use with ChromeVox next. Keep these

chrome/browser/resources/chromeos/accessibility/chromevox/background/locale_output_helper.js

@@ -12,8 +12,6 @@
 
 goog.provide('LocaleOutputHelper');
 
-goog.require('StringUtil');
-
 LocaleOutputHelper = class {
   /** @private */
   constructor() {
@@ -141,26 +139,14 @@ LocaleOutputHelper = class {
 
   /**
    * Creates a singleton instance of LocaleOutputHelper.
-   * @private
    */
   static init() {
-    if (LocaleOutputHelper.instance_ !== undefined) {
-      console.error(
-          'LocaleOutputHelper is a singleton, can only call |init| once');
-      return;
+    if (LocaleOutputHelper.instance !== undefined) {
+      throw new Error(
+          'LocaleOutputHelper is a singleton, can only initialize once');
     }
 
-    LocaleOutputHelper.instance_ = new LocaleOutputHelper();
-  }
-
-  /**
-   * @return {!LocaleOutputHelper}
-   */
-  static get instance() {
-    if (!LocaleOutputHelper.instance_) {
-      LocaleOutputHelper.init();
-    }
-    return LocaleOutputHelper.instance_;
+    LocaleOutputHelper.instance = new LocaleOutputHelper();
   }
 
   /**