[Fuchsia] Switch service protocol to bind to ipv6

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;
 
 final bool silentObservatory = const bool.fromEnvironment('SILENT_OBSERVATORY');
 
 void serverPrint(String s) {
   if (silentObservatory) {
@@ skipping 317 matching lines @@
       return this;
     }
 
     // Startup HTTP server.
     var pollError;
     var pollStack;
     Future<bool> poll() async {
       try {
         var address;
         if (Platform.isFuchsia) {
-          address = InternetAddress.ANY_IP_V4;
+          address = InternetAddress.ANY_IP_V6;
         } else {
           var addresses = await InternetAddress.lookup(_ip);
           // Prefer IPv4 addresses.
           for (var i = 0; i < addresses.length; i++) {
             address = addresses[i];
             if (address.type == InternetAddressType.IP_V4) break;
           }
         }
         _server = await HttpServer.bind(address, _port);
         return true;
@@ skipping 66 matching lines @@
       _server = null;
       serverPrint('Could not shutdown Observatory HTTP server:\n$e\n$st\n');
       _notifyServerState("");
       onServerAddressChange(null);
       return this;
     });
   }
 }
 
 void _notifyServerState(String uri) native "VMServiceIO_NotifyServerState";