Enable wallpaper boot animation for boot into sign in too. Add flag to disable it.

chrome/browser/resources/chromeos/login/display_manager.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 Display manager for WebUI OOBE and login.
  */
 
 // TODO(xiyuan): Find a better to share those constants.
 /** @const */ var SCREEN_OOBE_NETWORK = 'connect';
@@ skipping 343 matching lines @@
     isNewOobe: function() {
       return document.documentElement.getAttribute('oobe') == 'new';
     },
 
     /**
      * Returns true if the current screen is the lock screen.
      */
     isLockScreen: function() {
       return document.documentElement.getAttribute('screen') == 'lock';
     },
+
+    /**
+     * Returns true if sign in UI should trigger wallpaper load on boot.
+     */
+    shouldLoadWallpaperOnBoot: function() {
+      return localStrings.getString('bootIntoWallpaper') == 'on';
+    },
   };
 
   /**
    * Returns offset (top, left) of the element.
    * @param {!Element} element HTML element.
    * @return {!Object} The offset (top, left).
    */
   DisplayManager.getOffset = function(element) {
     var x = 0;
     var y = 0;
@@ skipping 117 matching lines @@
         });
       }
     }
   };
 
   // Export
   return {
     DisplayManager: DisplayManager
   };
 });