Make the Dart application library code stop using the "wrong way" service provider (a.k.a. exposed_…

mojo/dart/apptests/test_apps/echo/lib/main.dart

 // 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.
 
 import 'dart:async';
 
 import 'package:mojo/application.dart';
 import 'package:mojo/bindings.dart';
 import 'package:mojo/core.dart';
 import 'package:_mojo_for_test_only/test/echo_service.mojom.dart';
@@ skipping 39 matching lines @@
     });
   }
 }
 
 class EchoApplication extends Application {
   EchoApplication.fromHandle(MojoHandle handle) : super.fromHandle(handle);
 
   @override
   void acceptConnection(String requestorUrl, String resolvedUrl,
       ApplicationConnection connection) {
-    // No services are required from the remote end.
-    connection.remoteServiceProvider.close();
     connection.provideService(EchoService.serviceName,
         (endpoint) => new EchoServiceImpl(this, endpoint));
   }
 }
 
 main(List args, Object handleToken) {
   MojoHandle appHandle = new MojoHandle(handleToken);
   new EchoApplication.fromHandle(appHandle)
     ..onError = ((_) {
       MojoHandle.reportLeakedHandles();
     });
 }