ChromeOS: Implement Language Selection screen of material design OOBE.

chrome/browser/resources/chromeos/login/oobe.js

 // Copyright (c) 2012 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 Out of the box experience flow (OOBE).
  * This is the main code for the OOBE WebUI implementation.
  */
 
 <include src="login_shared.js">
@@ skipping 287 matching lines @@
       // Reload global local strings, process DOM tree again.
       loadTimeData.overrideValues(data);
       i18nTemplate.process(document, loadTimeData);
 
       // Update language and input method menu lists.
       Oobe.setupSelect($('language-select'), data.languageList);
       Oobe.setupSelect($('keyboard-select'), data.inputMethodsList);
       Oobe.setupSelect($('timezone-select'), data.timezoneList);
 
       // ---------- Welcome screen
-      $('oobe-welcome-md').currentLanguage =
-          Oobe.getSelectedTitle(data.languageList);
+      if (data.newOobeUI == 'on') {

[michaelpg, 2016/08/04 07:56:45]

We know at startup whether or not the md-oobe flag is enabled, so why do we
create the element when the --enable-md-oobe flag isn't enabled? Is this feature
effectively "launched" because the code runs on every device regardless of
flags?

+        var welcomeScreen = $('oobe-welcome-md');
+        welcomeScreen.currentLanguage =
+            Oobe.getSelectedTitle(data.languageList);
+        welcomeScreen.languages = data.languageList;
 
-      if (data.newOobeUI == 'on') {
+        welcomeScreen.keyboards = data.inputMethodsList;
+
         $('oobe-connect').hidden = true;
-        $('oobe-welcome-md').hidden = false;
+        welcomeScreen.hidden = false;
+        welcomeScreen.enabled = true;

[michaelpg, 2016/08/04 07:56:45]

I guess I would say if we want to enable/disable the MD welcome screen, we
should enable/disable the whole element, not just a Language section we want to
hide from tests.

       } else {
         $('oobe-connect').hidden = false;
         $('oobe-welcome-md').hidden = true;
       }
       // ----------
 
       // Update localized content of the screens.
       Oobe.updateLocalizedContent();
     },
 
     /**
      * Updates localized content of the screens.
      * Should be executed on language change.
      */
     updateLocalizedContent: function() {
       // Buttons, headers and links.
       Oobe.getInstance().updateLocalizedContent_();
     }
   };
 });