[cros] User image selection wraps when navigating with arrow keys.

chrome/browser/resources/chromeos/login/oobe_screen_user_image.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.
 
 /**
  * @fileoverview Oobe user image screen implementation.
  */
 
 cr.define('oobe', function() {
   /**
@@ skipping 107 matching lines @@
       UserImageScreen.addUserImage(
           imageUrl,
           UserImageScreen.handleImageClick);
     }
 
     var userImageScreen = $('user-image');
     var userImageList = $('user-image-list');
     userImageList.addEventListener('keydown', function(e) {
       var prevIndex = userImageScreen.selectedUserImage_;
       var len = userImageList.children.length;
-      if (e.keyCode == 39 || e.keyCode == 40) {  // right or down
-        if (prevIndex < len - 1)
-          UserImageScreen.selectUserImage(prevIndex + 1);
-      } else if (e.keyCode == 37 || e.keyCode == 38) {  // left or up
-        if (prevIndex > 0)
-          UserImageScreen.selectUserImage(prevIndex - 1);
-      }
+      if (e.keyCode == 39 || e.keyCode == 40)  // right or down
+        UserImageScreen.selectUserImage((prevIndex + 1) % len);
+      else if (e.keyCode == 37 || e.keyCode == 38)  // left or up
+        UserImageScreen.selectUserImage((prevIndex - 1 + len) % len);
       e.stopPropagation();
     });
   };
 
   /**
    * Selects the specified user image and shows it in preview.
    * @param {number} index The index of the image to select.
    */
   UserImageScreen.selectUserImage = function(index) {
     var userImageList = $('user-image-list');
@@ skipping 10 matching lines @@
       selectedImage.focus();
       $('user-image-preview').src = selectedImage.src;
     }
     userImageScreen.selectedUserImage_ = index;
   };
 
   return {
     UserImageScreen: UserImageScreen
   };
 });