Dart: Refactor Stubs

mojo/dart/unittests/embedder_tests/validation_test.dart

 // Copyright 2015 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.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:isolate';
 import 'dart:mojo.builtin' as builtin;
 import 'dart:typed_data';
 
 import 'package:_mojo_for_test_only/validation_test_input_parser.dart' as parser;
 import 'package:mojo/bindings.dart';
 import 'package:mojo/core.dart';
 import 'package:_mojo_for_test_only/mojo/test/validation_test_interfaces.mojom.dart';
 
 class ConformanceTestInterfaceImpl implements ConformanceTestInterface {
   ConformanceTestInterfaceStub _stub;
   Completer _completer;
 
   ConformanceTestInterfaceImpl(
       this._completer, MojoMessagePipeEndpoint endpoint) {
     _stub = new ConformanceTestInterfaceStub.fromEndpoint(endpoint, this);
   }
 
   set onError(Function f) {
-    _stub.onError = f;
+    _stub.ctrl.onError = f;
   }
 
   void _complete() => _completer.complete(null);
 
   method0(double param0) => _complete();
   method1(StructA param0) => _complete();
   method2(StructB param0, StructA param1) => _complete();
   method3(List<bool> param0) => _complete();
   method4(StructC param0, List<int> param1) => _complete();
   method5(StructE param0, MojoDataPipeProducer param1) {
@@ skipping 89 matching lines @@
     try {
       await runTest(name, parser.parse(data), expected);
       print('$name PASSED.');
     } catch (e) {
       print('$name FAILED: $e');
     }
   }
   // TODO(zra): Add integration tests when they no longer rely on Client=
   MojoHandle.reportLeakedHandles();
 }