Add NetworkAdaptor to dart:io.

tests/standalone/io/network_interface_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 "package:expect/expect.dart";
+
+
+void testListLoopback() {
+  NetworkInterface.list(includeLoopback: false).then((list) {
+    for (var i in list) {
+      for (var a in i.addresses) {
+        Expect.isFalse(a.isLoopback);
+      }
+    }
+  });
+
+  NetworkInterface.list(includeLoopback: true).then((list) {
+    Expect.isTrue(list.any((i) => i.addresses.any((a) => a.isLoopback)));
+  });
+}
+
+
+void testListLinkLocal() {
+  NetworkInterface.list(includeLinkLocal: false).then((list) {
+    for (var i in list) {
+      for (var a in i.addresses) {
+        Expect.isFalse(a.isLinkLocal);
+      }
+    }
+  });
+}
+
+
+void main() {
+  testListLoopback();
+  testListLinkLocal();
+}