Change InternetAddress back to abstract and make the constructor a factory

sdk/lib/io/socket.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 dart.io;
 
 
 /**
  * [InternetAddressType] is the type an [InternetAddress]. Currently,
  * IP version 4 (IPv4) and IP version 6 (IPv6) are supported.
@@ skipping 28 matching lines @@
   String toString() => "InternetAddressType: $name";
 }
 
 
 /**
  * The [InternetAddress] is an object reflecting either a remote or a
  * local address. When combined with a port number, this represents a
  * endpoint that a socket can connect to or a listening socket can
  * bind to.
  */
-class InternetAddress {
+abstract class InternetAddress {
   /**
    * IP version 4 loopback address. Use this address when listening on
    * or connecting to the loopback adapter using IP version 4 (IPv4).
    */
   external static InternetAddress get LOOPBACK_IP_V4;
 
   /**
    * IP version 6 loopback address. Use this address when listening on
    * or connecting to the loopback adapter using IP version 6 (IPv6).
    */
@@ skipping 44 matching lines @@
    */
   bool get isMulticast;
 
   /**
    * Creates a new [InternetAddress] from a numeric address.
    *
    * If the address in [address] is not a numeric IPv4
    * (dotted-decimal notation) or IPv6 (hexadecimal representation).
    * address [ArgumentError] is thrown.
    */
-  external InternetAddress(String address);
+  external factory InternetAddress(String address);
 
   /**
    * Perform a reverse dns lookup on the [address], creating a new
    * [InternetAddress] where the host field set to the result.
    */
   Future<InternetAddress> reverse();
 
   /**
    * Lookup a host, returning a Future of a list of
    * [InternetAddress]s. If [type] is [InternetAddressType.ANY], it
@@ skipping 400 matching lines @@
     }
     if (address != null) {
       sb.write(", address = ${address.host}");
     }
     if (port != null) {
       sb.write(", port = $port");
     }
     return sb.toString();
   }
 }