Copy site/try/project_server.dart to pkg/dart2js_incremental/lib/

dart/pkg/dart2js_incremental/lib/server.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library trydart.projectServer;
 
 import 'dart:io';
 
 import 'dart:async' show
     Future,
@@ skipping 435 matching lines @@
     Conversation.packageRoot = Uri.base.resolve(arguments[4]);
   }
   HttpServer.bind(host, port).then((HttpServer server) {
     print('HTTP server started on http://$host:${server.port}/');
     server.listen(Conversation.onRequest, onError: Conversation.onError);
   }).catchError((e) {
     print("HttpServer.bind error: $e");
     exit(1);
   });
 }