Extract common code, add host IP to --debug and --enable-vm-service options

dart/runtime/bin/vmservice/server.dart

 // Copyright (c) 2013, 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.
 
 part of vmservice_io;
 
 class WebSocketClient extends Client {
   static const int PARSE_ERROR_CODE = 4000;
   static const int BINARY_MESSAGE_ERROR_CODE = 4001;
   static const int NOT_MAP_ERROR_CODE = 4002;
@@ skipping 63 matching lines @@
     Map map = super.toJson();
     map['type'] = 'HttpRequestClient';
     map['request'] = '$request';
     return map;
   }
 }
 
 class Server {
   static const WEBSOCKET_PATH = '/ws';
   String defaultPath = '/index.html';
+  final String ip;
   int port;
 
   final VMService service;
   HttpServer _server;
 
-  Server(this.service, this.port);
+  Server(this.service, this.ip, this.port);
 
   void _requestHandler(HttpRequest request) {
     // Allow cross origin requests.
     request.response.headers.add('Access-Control-Allow-Origin', '*');
 
     final String path =
           request.uri.path == '/' ? defaultPath : request.uri.path;
 
     var resource = Resource.resources[path];
     if (resource != null) {
@@ skipping 11 matching lines @@
       });
       return;
     }
 
     var message = new Message.fromUri(request.uri);
     var client = new HttpRequestClient(request, service);
     client.onMessage(null, message);
   }
 
   Future startServer() {
-    return HttpServer.bind(InternetAddress.LOOPBACK_IP_V4, port).then((s) {
+    return HttpServer.bind(ip, port).then((s) {
       // Only display message when port is automatically selected.
-      var display_message = (port == 0);
+      var display_message = (ip != '127.0.0.1' || port != 8181);
       // Retrieve port.
       port = s.port;
       _server = s;
       _server.listen(_requestHandler);
       if (display_message) {
-        print('VMService listening on port $port');
+        print('VMService listening on $ip:$port');
       }
       return s;
     });
   }
 }