Remove observer when switching from import overlay to create profile overlay.

chrome/browser/resources/options/managed_user_import.js

 // Copyright 2013 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.
 
 cr.define('options', function() {
   var OptionsPage = options.OptionsPage;
   var ArrayDataModel = cr.ui.ArrayDataModel;
 
   /**
    * ManagedUserImportOverlay class.
@@ skipping 48 matching lines @@
         self.updateImportInProgress_(false);
 
         // 'cancelCreateProfile' is handled by CreateProfileHandler.
         chrome.send('cancelCreateProfile');
       };
 
       $('managed-user-import-ok').onclick =
           this.showAvatarGridOrSubmit_.bind(this);
 
       $('create-new-user-link').onclick = function(event) {
+        options.ManagedUserListData.removeObserver(self);
         OptionsPage.navigateToPage('createProfile');
       };
     },
 
     /**
      * @override
      */
     didShowPage: function() {
       options.ManagedUserListData.requestExistingManagedUsers().then(
           this.receiveExistingManagedUsers_, this.onSigninError_.bind(this));
@@ skipping 155 matching lines @@
       var instance = ManagedUserImportOverlay.getInstance();
       return instance[name + '_'].apply(instance, arguments);
     };
   });
 
   // Export
   return {
     ManagedUserImportOverlay: ManagedUserImportOverlay,
   };
 });