MD User Manager: "Select an account" should just be a label not a menu entry

chrome/browser/resources/md_user_manager/create_profile.js

 // Copyright 2016 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 'create-profile' is a page that contains controls for creating
  * a (optionally supervised) profile, including choosing a name, and an avatar.
  */
 
 /** @typedef {{url: string, label:string}} */
@@ skipping 89 matching lines @@
 
     /**
      * Index of the selected signed-in user.
      * @private {number}
      */
     signedInUserIndex_: {
       type: Number,
       value: NO_USER_SELECTED
     },
 
-    /**
-     * Sentinel signed-in user's index value.
-     * @private {number}
-     */
-    sentinelSignedInUserIndex_: {
-      type: Number,
-      value: NO_USER_SELECTED,
-      readOnly: true
-    },
-
     /** @private {!signin.ProfileBrowserProxy} */
     browserProxy_: Object
   },
 
   listeners: {
     'tap': 'onTap_',
     'importUserPopup.import': 'onImportUserPopupImport_'
   },
 
   /** @override */
@@ skipping 360 matching lines @@
    * Computed binding that returns True if there are any signed-in users.
    * @param {!Array<!SignedInUser>} signedInUsers signed-in users.
    * @return {boolean}
    * @private
    */
   isSignedIn_: function(signedInUsers) {
     return signedInUsers.length > 0;
   }
 });
 }());