Add exists, create and delete to directory implementation on Linux and Mac.

runtime/bin/directory_win.cc

 // Copyright (c) 2011, 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.
 
 #include "bin/directory.h"
 
 // Forward declaration.
 static bool ListRecursively(const char* dir_name,
                             bool recursive,
                             Dart_Port dir_port,
@@ skipping 137 matching lines @@
 
   completed = completed && (GetLastError() == ERROR_NO_MORE_FILES);
 
   // TODO(ager): Post on error port if close fails.
   FindClose(find_handle);
   free(path);
 
   return completed;
 }
 
+
 void Directory::List(const char* dir_name,
                      bool recursive,
                      Dart_Port dir_port,
                      Dart_Port file_port,
                      Dart_Port done_port,
                      Dart_Port error_port) {
   bool result = ListRecursively(dir_name,
                                 recursive,
                                 dir_port,
                                 file_port,
                                 done_port,
                                 error_port);
   if (done_port != 0) {
     Dart_Handle value = Dart_NewBoolean(result);
     Dart_Post(done_port, value);
   }
 }
+
+
+bool Directory::Exists(const char* dir_name, bool* result) {
+  UNIMPLEMENTED();
+  return false;
+}
+
+
+bool Directory::Create(const char* dir_name) {
+  UNIMPLEMENTED();
+  return false;
+}
+
+
+bool Directory::Delete(const char* dir_name) {
+  UNIMPLEMENTED();
+  return false;
+}