Added usage of ScreenContext in EulaScreen.

ui/login/screen.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 Base class for all login WebUI screens.
  */
 cr.define('login', function() {
   /** @const */ var CALLBACK_USER_ACTED = 'userActed';
   /** @const */ var CALLBACK_CONTEXT_CHANGED = 'contextChanged';
@@ skipping 25 matching lines @@
       return this.screenContext_;
     },
 
     /**
      * Dictionary of context observers that are methods of |this| bound to
      * |this|.
      */
     contextObservers_: null,
 
     /**
-     * Called during screen registration.
+     * Called during screen initialization.
      */
     decorate: doNothing,
 
     /**
      * Returns minimal size that screen prefers to have. Default implementation
      * returns current screen size.
      * @return {{width: number, height: number}}
      */
     getPreferredSize: function() {
       return {width: this.offsetWidth, height: this.offsetHeight};
@@ skipping 52 matching lines @@
      *  * Creates screen context.
      *  * Looks for elements having "alias" property and adds them as the
      *    proprties of the screen with name equal to value of "alias", i.e. HTML
      *    element <div alias="myDiv"></div> will be stored in this.myDiv.
      *  * Looks for buttons having "action" properties and adds click handlers
      *    to them. These handlers send |CALLBACK_USER_ACTED| messages to
      *    C++ with "action" property's value as payload.
      * @private
      */
     initializeImpl_: function() {
-      this.screenContext_ = new login.ScreenContext();
+      if (cr.isChromeOS)
+        this.screenContext_ = new login.ScreenContext();
+
+      this.decorate();
+
       this.querySelectorAllImpl_('[alias]').forEach(function(element) {
         var alias = element.getAttribute('alias');
         if (alias in this)
           throw Error('Alias "' + alias + '" of "' + this.name() + '" screen ' +
               'shadows or redefines property that is already defined.');
         this[alias] = element;
         this[element.getAttribute('alias')] = element;
       }, this);
       var self = this;
       this.querySelectorAllImpl_('button[action]').forEach(function(button) {
@@ skipping 183 matching lines @@
       Constructor.prototype.name = function() { return id; };
 
       api.contextChanged = function() {
         var screen = $(id);
         screen.contextChanged_.apply(screen, arguments);
       }
 
       api.register = function() {
         var screen = $(id);
         screen.__proto__ = new Constructor();
-        screen.decorate();
+        screen.initialize();
         Oobe.getInstance().registerScreen(screen);
       };
 
       cr.define('login', function() {
         var result = {};
         result[name] = api;
         return result;
       });
     }
   };
 });