Revert "Revert "Start of 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 622623a33184ac2043b82394bbb84e6b50244ff2..79b036df6c1caef674cad0ef24ec5799ce7db8f6 100644
--- a/tests/html/custom/document_register_type_extensions_test.dart
+++ b/tests/html/custom/document_register_type_extensions_test.dart
@@ -60,9 +60,9 @@ 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);