Dartium custom element lifecycle event support.

tests/html/custom/document_register_type_extensions_test.dart

Index: tests/html/custom/document_register_type_extensions_test.dart
diff --git a/tests/html/custom/document_register_type_extensions_test.dart b/tests/html/custom/document_register_type_extensions_test.dart
index cae07a15389b93df44ee4446bb696e949b847d53..cf1337493fc39fceb813a6fe7c1da77167ed59da 100644
--- a/tests/html/custom/document_register_type_extensions_test.dart
+++ b/tests/html/custom/document_register_type_extensions_test.dart
@@ -72,9 +72,9 @@ main() {
     }
     registeredTypes = true;
     document.register(Foo.tag, Foo);
-    document.register(Bar.tag, Bar);
+    document.register(Bar.tag, Bar, extendsTag: 'input');
     document.register(Baz.tag, Baz);
-    document.register(Qux.tag, Qux);
+    document.register(Qux.tag, Qux, extendsTag: 'input');
   }
 
   setUp(loadPolyfills);