New Guest mode avatar on the start screen

chrome/browser/resources/chromeos/login/user_pod_row.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 User pod row implementation.
  */
 
 cr.define('login', function() {
   /**
@@ skipping 306 matching lines @@
         this.removeUserButtonElement.classList.remove('active');
         this.removeUserButtonElement.textContent = '';
       }
     },
 
     /**
      * Updates the image element of the user.
      */
     updateUserImage: function() {
       this.imageElement.src = this.isGuest ?
-          'chrome://theme/IDR_LOGIN_GUEST' :
+          'chrome://theme/IDR_LOGIN_GUEST@' + window.devicePixelRatio + 'x' :
           'chrome://userimage/' + this.user.username +
               '?id=' + (new Date()).getTime() + '&animated';
     },
 
     /**
      * Focuses on input element.
      */
     focusInput: function() {
       if (!this.isGuest) {
         var needSignin = this.needGaiaSignin;
@@ skipping 581 matching lines @@
           chrome.send('loginVisible');
         });
       }
     }
   };
 
   return {
     PodRow: PodRow
   };
 });