Add new InternetAddress class with a static lookup function (including IPv6 results).

tests/standalone/io/socket_ipv6_test.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.
+
+import 'dart:io';
+import 'dart:isolate';
+
+void testIPv6toIPv6() {
+  ServerSocket.bind("::0").then((server) {
+    server.listen((socket) {
+      socket.destroy();
+      server.close();
+    });
+    Socket.connect("::1", server.port).then((socket) {
+      socket.destroy();
+    });
+  });
+}
+
+void testIPv4toIPv6() {
+  ServerSocket.bind("::0").then((server) {
+    server.listen((socket) {
+      socket.destroy();
+      server.close();
+    });
+    Socket.connect("127.0.0.1", server.port).then((socket) {
+      socket.destroy();
+    });
+  });
+}
+
+void testIPv6toIPv4() {
+  ServerSocket.bind("127.0.0.1").then((server) {
+    server.listen((socket) {
+      throw "Unexpected socket";
+    });
+    Socket.connect("::1", server.port).catchError((e) {
+      server.close();
+    });
+  });
+}
+
+void testIPv4toIPv4() {
+  ServerSocket.bind("127.0.0.1").then((server) {
+    server.listen((socket) {
+      socket.destroy();
+      server.close();
+    });
+    Socket.connect("127.0.0.1", server.port).then((socket) {
+      socket.destroy();
+    });
+  });
+}
+
+void testIPv6Lookup() {
+  var port = new ReceivePort();
+  InternetAddress.lookup("::0").then((list) {
+    if (list.length < 0) throw "no address";
+    for (var entry in list) {
+      if (entry.type != InternetAddressType.IPv6) {
+        throw "Wrong IP type";
+      }
+    }
+    port.close();
+  });
+}
+
+void testIPv4Lookup() {
+  var port = new ReceivePort();
+  InternetAddress.lookup("127.0.0.1").then((list) {
+    if (list.length < 0) throw "no addresse";
+    for (var entry in list) {
+      if (entry.type != InternetAddressType.IPv4) {
+        throw "Wrong IP type";
+      }
+    }
+    port.close();
+  });
+}
+
+void main() {
+  testIPv6toIPv6();
+  testIPv4toIPv6();
+  testIPv6toIPv4();
+  testIPv4toIPv4();
+  testIPv6Lookup();
+  testIPv4Lookup();
+}