Reapply remove upgradeCustomElement methods.

tests/html/custom_elements_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library custom_elements_test;
 import 'dart:async';
 import 'dart:html';
 import 'package:unittest/html_individual_config.dart';
 import 'package:unittest/unittest.dart';
 import 'utils.dart';
@@ skipping 100 matching lines @@
       var preElement = dom.children[0];
       expect(preElement, isNotNull);
       expect(preElement is HtmlElement, isTrue);
       expect(preElement is CustomType, isFalse);
       var firedOnPre = false;
       preElement.onFocus.listen((_) {
         firedOnPre = true;
       });
 
       document.register(tag, CustomType);
-      Platform.upgradeCustomElements(dom);
+      upgradeCustomElements(dom);
 
       var postElement = dom.children[0];
       expect(postElement, isNotNull);
       expect(postElement is CustomType, isTrue);
       expect(postElement.createdCalled, isTrue);
 
       // Element from first query remains an UnknownElement.
       expect(preElement is HtmlElement, isTrue);
       expect(preElement.parent, dom);
       expect(dom.children.length, 1);
 
       var firedOnPost = false;
       postElement.onFocus.listen((_) {
         firedOnPost = true;
       });
       // Event handlers persist on old and new element.
       postElement.dispatchEvent(new Event('focus'));
       expect(firedOnPre, isTrue);
       expect(firedOnPost, isTrue);
     });
   });*/
 
   group('innerHtml', () {
     test('query', () {
       var tag = nextTag;
       document.register(tag, CustomType);
       var element = new DivElement();
       element.setInnerHtml('<$tag></$tag>',
           treeSanitizer: new NullTreeSanitizer());
-          Platform.upgradeCustomElements(element);
+          upgradeCustomElements(element);
       document.body.nodes.add(element);
       var queried = query(tag);
 
       expect(queried, isNotNull);
       expect(queried is CustomType, isTrue);
       expect(queried.createdCalled, isTrue);
     });
 
     test('query id', () {
       var tag = nextTag;
       document.register(tag, CustomType);
       var element = new DivElement();
       element.setInnerHtml('<$tag id="someid"></$tag>',
           treeSanitizer: new NullTreeSanitizer());
-          Platform.upgradeCustomElements(element);
+          upgradeCustomElements(element);
       document.body.nodes.add(element);
       var queried = query('#someid');
 
       expect(queried, isNotNull);
       expect(queried is CustomType, isTrue);
       expect(queried.id, "someid");
     });
   });
 
   group('lifecycle', () {
     test('created', () {
       int oldCount = customCreatedCount;
       var tag = nextTag;
       document.register(tag, CustomType);
       var element = new DivElement();
       element.setInnerHtml('<$tag></$tag>',
           treeSanitizer: new NullTreeSanitizer());
-      Platform.upgradeCustomElements(element);
+      upgradeCustomElements(element);
       document.body.nodes.add(element);
       expect(customCreatedCount, oldCount + 1);
     });
   });
 
   group('mixins', () {
     test('can invoke mixin methods', () {
       var tag = nextTag;
       document.register(tag, CustomType);
 
       var element = new Element.tag(tag);
       element.invokeMixinMethod();
       expect(element.mixinMethodCalled, isTrue);
     });
   });
 }