Dart: Adjusts class Application for removal of Application/Shell Client=

services/dart/test/pingpong.dart

 #!mojo mojo:dart_content_handler
 
 // 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:mojo_application';
 import 'dart:mojo_bindings';
 import 'dart:mojo_core';
@@ skipping 76 matching lines @@
   getPingPongService(PingPongServiceStub stub) {
     stub.delegate = new PingPongServiceImpl.unbound();
     stub.listen();
   }
 
   void quit() {
     if (_proxy != null) {
       _proxy.close();
     }
     close();
+    if (_application != null) {
+      _application.close();
+    }
   }
 }
 
 class PingPongApplication extends Application {
   PingPongApplication.fromHandle(MojoHandle handle) : super.fromHandle(handle);
 
   Function stubFactoryClosure() =>
       (endpoint) => new PingPongServiceImpl(this, endpoint);
 }
 
 main(List args) {
-  MojoHandle shellHandle = new MojoHandle(args[0]);
+  MojoHandle appHandle = new MojoHandle(args[0]);
   String url = args[1];
-  var pingPongApplication = new PingPongApplication.fromHandle(shellHandle);
+  var pingPongApplication = new PingPongApplication.fromHandle(appHandle);
   pingPongApplication.listen();
 }