Allow paths up to 32767 characters on Windows (so '\\?\' can be used).

tests/standalone/io/file_windows_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 testDeleteLongPathPrefix() {
+  var dir = Directory.systemTemp.createTempSync('dart_file_win');
+  var prefixDir = new Directory('\\\\?\\${dir.path}');

[Søren Gjesse, 2014/02/04 13:53:05]

Please create a number of sub directories so the longest path exceeds 256
characters.

[Anders Johnsen, 2014/02/04 14:00:21]

Done.

+  Expect.isTrue(prefixDir.existsSync());
+  prefixDir.deleteSync(recursive: true);
+  Expect.isFalse(dir.existsSync());
+  Expect.isFalse(prefixDir.existsSync());
+}
+
+
+void main() {
+ // if (!Platform.isWindows) return;

[Søren Gjesse, 2014/02/04 13:53:05]

Remember to un-comment this line.

[Anders Johnsen, 2014/02/04 14:00:21]

Done.

+  testDeleteLongPathPrefix();
+}