Change File.directory to not do any IO

tests/standalone/io/file_error_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.
 //
 // Dart test program for testing error handling in file I/O.
 
 import "package:expect/expect.dart";
 import "dart:io";
 import "dart:isolate";
 
@@ skipping 153 matching lines @@
                 (e) => checkFullPathOnNonExistentDirectoryException(e));
 
   var fullPathFuture = file.fullPath();
   fullPathFuture.then((path) => Expect.fail("Unreachable code $path"))
   .catchError((error) {
     checkFullPathOnNonExistentDirectoryException(error);
     p.toSendPort().send(null);
   });
 }
 
-bool checkDirectoryInNonExistentDirectoryException(e) {
-  Expect.isTrue(e is FileIOException);
-  Expect.isTrue(e.osError != null);
-  Expect.isTrue(
-      e.toString().indexOf("Cannot retrieve directory for file") != -1);
-  // File not not found has error code 2 on all supported platforms.
-  Expect.equals(2, e.osError.errorCode);
-
-  return true;
-}
-
-void testDirectoryInNonExistentDirectory() {
-  Directory temp = tempDir();
-  ReceivePort p = new ReceivePort();
-  p.receive((x, y) {
-    p.close();
-    temp.deleteSync(recursive: true);
-  });
-  var file = new File("${temp.path}/nonExistentDirectory/newFile");
-
-  // Create in non-existent directory should throw exception.
-  Expect.throws(() => file.directorySync(),
-                (e) => checkDirectoryInNonExistentDirectoryException(e));
-
-  var dirFuture = file.directory();
-  dirFuture.then((directory) => Expect.fail("Unreachable code"))
-  .catchError((error) {
-    checkDirectoryInNonExistentDirectoryException(error);
-    p.toSendPort().send(null);
-  });
-}
-
 void testReadAsBytesNonExistent() {
   Directory temp = tempDir();
   ReceivePort p = new ReceivePort();
   p.receive((x, y) {
     p.close();
     temp.deleteSync(recursive: true);
   });
   var file = new File("${temp.path}/nonExistentFile3");
 
   // Non-existing file should throw exception.
@@ skipping 258 matching lines @@
     port.send(null);
   });
 }
 
 main() {
   testOpenNonExistent();
   testDeleteNonExistent();
   testLengthNonExistent();
   testCreateInNonExistentDirectory();
   testFullPathOnNonExistentDirectory();
-  testDirectoryInNonExistentDirectory();
   testReadAsBytesNonExistent();
   testReadAsTextNonExistent();
   testReadAsLinesNonExistent();
   testWriteByteToReadOnlyFile();
   testWriteFromToReadOnlyFile();
   testTruncateReadOnlyFile();
   testOperateOnClosedFile();
   testRepeatedlyCloseFile();
   testRepeatedlyCloseFileSync();
   testReadSyncBigInt();
   testReadSyncClosedFile();
 }