Rationalize Dart mojo and sky package structure

mojo/public/dart/lib/src/application_connection.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.
 
 part of application;
 
 typedef Object ServiceFactory(core.MojoMessagePipeEndpoint endpoint);
 typedef void FallbackServiceFactory(
     String interfaceName, core.MojoMessagePipeEndpoint endpoint);
 
@@ skipping 101 matching lines @@
     }
     if (_localServiceProvider != null) {
       lspCloseFuture = _localServiceProvider.close(immediate: immediate);
       _localServiceProvider = null;
     } else {
       lspCloseFuture = new Future.value(null);
     }
     return rspCloseFuture.then((_) => lspCloseFuture);
   }
 }