ChromeOS OOBE: Fix EULA Back button.

chrome/browser/resources/chromeos/login/oobe_dialog.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.
 
 Polymer({
   is: 'oobe-dialog',
 
   properties: {
     /**
      * Controls visibility of the bottom-buttons element.
      */
     hasButtons: {
       type: Boolean,
       value: false,
     },
 
     /**
      * Switches styles to "Welcome screen".
      */
     welcomeScreen: {
       type: Boolean,
       value: false,
       reflectToAttribute: true,
     },
   },
 
-  focus: function() {},
+  focus: function() {
+    /* When Network Selection Dialog is shown because user pressed "Back"
+       button on EULA screen display_manager does not inform this dialog that
+       it is shown. It ouly focuses this dialog.
+       So this emulates show().
+       TODO (alemate): fix this once event flow is updated.

[achuithb, 2017/02/20 01:08:16]

Is there a bug?

[Alexander Alekseev, 2017/02/21 21:55:44]

It should probably be called "remove old OOBE code", but we don't have any issue
like this yet.

+    */
+    this.show();
+  },
 
   /**
     * This is called from oobe_welcome when this dialog is shown.
     */
   show: function() {
     var focusedElements = this.getElementsByClassName('focus-on-show');
     if (focusedElements)
       focusedElements[0].focus();
 
     this.fire('show-dialog');
   },
 });