Enable user change background image in settings page in Aura build.

chrome/browser/resources/options2/options_bundle.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.
 //
 // This file exists to aggregate all of the javascript used by the
 // settings page into a single file which will be flattened and served
 // as a single resource.
 <include src="controlled_setting.js"></include>
 <include src="deletable_item_list.js"></include>
 <include src="inline_editable_list.js"></include>
@@ skipping 25 matching lines @@
   <include src="chromeos/virtual_keyboard_list.js"></include>
   var AccountsOptions = options.AccountsOptions;
   var ChangePictureOptions = options.ChangePictureOptions;
   var InternetOptions = options.InternetOptions;
   var DetailsInternetPage = options.internet.DetailsInternetPage;
   var BluetoothOptions = options.BluetoothOptions;
   var BluetoothPairing = options.BluetoothPairing;
   var KeyboardOverlay = options.KeyboardOverlay;
   var PointerOverlay = options.PointerOverlay;
 </if>
+<if expr="pp_ifdef('use_ash')">
+  <include src="chromeos/set_wallpaper_options.js"></include>
+  var SetWallpaperOptions = options.SetWallpaperOptions;
+</if>
 <if expr="not is_win and not is_macosx">
   <include src="certificate_tree.js"></include>
   <include src="certificate_manager.js"></include>
   <include src="certificate_restore_overlay.js"></include>
   <include src="certificate_backup_overlay.js"></include>
   <include src="certificate_edit_ca_trust_overlay.js"></include>
   <include src="certificate_import_error_overlay.js"></include>
   var CertificateManager = options.CertificateManager;
   var CertificateRestoreOverlay = options.CertificateRestoreOverlay;
   var CertificateBackupOverlay = options.CertificateBackupOverlay;
@@ skipping 30 matching lines @@
 <include src="password_manager_list.js"></include>
 <include src="profiles_icon_grid.js"></include>
 <include src="search_engine_manager.js"></include>
 <include src="search_engine_manager_engine_list.js"></include>
 <include src="search_page.js"></include>
 <include src="session_restore_overlay.js"></include>
 <include src="startup_overlay.js"></include>
 <include src="../sync_setup_overlay.js"></include>
 <include src="../uber/uber_utils.js"></include>
 <include src="options.js"></include>