Add close button to the supervised user pages.

chrome/browser/resources/chromeos/login/screen_supervised_user_creation.js

 // Copyright 2014 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 Legacy supervised user creation flow screen.
  */
 
 login.createScreen('SupervisedUserCreationScreen',
                    'supervised-user-creation', function() {
@@ skipping 598 matching lines @@
       this.getScreenElement('flip-photo').addEventListener(
           'click', this.handleFlipPhoto_.bind(this));
       this.getScreenElement('image-stream-crop').addEventListener(
           'webkitTransitionEnd', function(e) {
             previewElement.classList.remove('animation');
           });
       this.getScreenElement('image-preview-img').addEventListener(
           'webkitTransitionEnd', function(e) {
             previewElement.classList.remove('animation');
           });
+
+      $('supervised-user-creation-close-button-item').addEventListener(
+          'mousedown', function(e) {
+            e.preventDefault();

[dzhioev (left Google), 2015/05/15 02:35:20]

This trick is not needed for "gaia-icon-button" as well

[achuithb, 2015/05/15 22:10:14]

Done.

+          });
+
+      $('supervised-user-creation-close-button-item').addEventListener(
+          'click', function(e) {
+            this.cancel();
+            e.preventDefault();
+          }.bind(this));
     },
 
     buttonIds: [],
 
     /**
      * Creates button for adding to controls.
      * @param {string} buttonId -- id for button, have to be unique within
      *   screen. Actual id will be prefixed with screen name and appended with
      *   '-button'. Use getScreenButton(buttonId) to find it later.
      * @param {string} i18nPrefix -- screen prefix for i18n values.
@@ skipping 957 matching lines @@
 
       if (selectedIndex >= 0)
         this.importList_.selectPod(this.importList_.pods[selectedIndex]);
 
       if (this.currentPage_ == 'username')
         this.getScreenElement('import-link').hidden = (userList.length == 0);
     },
   };
 });