Put Sync Encryption UI behind command line switch.

chrome/browser/resources/options/sync_setup_overlay.js

 // Copyright (c) 2011 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.
 
 cr.define('options', function() {
   const OptionsPage = options.OptionsPage;
 
   // Variable to track if a captcha challenge was issued. If this gets set to
   // true, it stays that way until we are told about successful login from
   // the browser.  This means subsequent errors (like invalid password) are
@@ skipping 379 matching lines @@
       var datatypeSelect = document.getElementById('sync-select-datatypes');
       var self = this;
       datatypeSelect.onchange = function() {
         var syncAll = this.selectedIndex == 0;
         self.setCheckboxesToKeepEverythingSynced_(syncAll);
       };
 
       $('sync-setup-configure').classList.remove('hidden');
 
       if (args) {
+        if (!args['encryptionEnabled'])
+          $('customize-sync-encryption').classList.add('hidden');
         this.setCheckboxesAndErrors_(args);
 
         // Whether to display the 'Sync everything' confirmation page or the
         // customize data types page.
         var showSyncEverythingPage = args['showSyncEverythingPage'];
         var keepEverythingSynced = args['keepEverythingSynced'];
         this.usePassphrase_ = args['usePassphrase'];
         if (showSyncEverythingPage == false ||
             keepEverythingSynced == false || this.usePassphrase_) {
           this.showCustomizePage_(keepEverythingSynced);
@@ skipping 289 matching lines @@
 
   SyncSetupOverlay.showSuccessAndSettingUp = function() {
     SyncSetupOverlay.getInstance().showSuccessAndSettingUp_();
   };
 
   // Export
   return {
     SyncSetupOverlay: SyncSetupOverlay
   };
 });