Add Directory.createTemp() to asynchronously create a temporary directory.

runtime/bin/directory.dart

 // 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.
 
 interface Directory factory _Directory {
   /**
    * Creates a directory object. The path is either a full path or
    * relative to the directory in which the Dart VM was
    * started.
    */
   Directory(String path);
 
   /**
    * Returns whether a directory with this name already exists.
    */
   bool existsSync();
 
   /**
    * Creates the directory with this name if it does not exist.
    * Throw an exception if the directory already exists.
    */
   void createSync();
 
   /**
+   * Creates a temporary directory with a name based on the current path.
+   * This name and path is used as a template, and additional characters are
+   * appended to it by the call to make a unique directory name.  If the
+   * path is the empty string, a default system temp directory and name
+   * are used for the template.
+   * The path is modified to be the path of the new directory.
+   * After the new directory is created, and the path modified, the callback
+   * createTempHandler will be called.  The error handler is called if
+   * the temporary directory cannot be created.
+   */
+  void createTemp();
+
+  /**
    * Deletes the directory with this name. Throws an exception
    * if the directory is not empty or if deletion failed.
    */
   void deleteSync();
 
   /**
    * List the sub-directories and files of this
    * [Directory]. Optionally recurse into sub-directories. For each
    * file and directory, the file or directory handler is called. When
    * all directories have been listed the done handler is called. If
@@ skipping 17 matching lines @@
   void set fileHandler(void fileHandler(String file));
 
   /**
    * Set the handler that is called when a directory listing is
    * done. The handler is called with an indication of whether or not
    * the listing operation completed.
    */
   void set doneHandler(void doneHandler(bool completed));
 
   /**
-   * Sets the handler that is called on error listing directories.
+   * Set the handler that is called when a temporary directory is created.

[Mads Ager (google), 2011/11/21 16:29:37]

Maybe shorten this to just state that it is called when a temporary directory is
*successfully* created and leave out the part about the error handler?

[Bill Hesse, 2011/11/22 12:49:39]

Done.

+   * The handler is called when the directory creation is completed.
+   * The error handler is called if the directory creation fails.
+   */
+  void set createTempHandler(void doneHandler(bool completed));
+
+  /**
+   * Sets the handler that is called if there is an error while listing
+   * or creating directories.
    */
   void set errorHandler(void errorHandler(String error));
 
   /**
    * Gets the path of this directory.
    */
   final String path;
 }
 
 
 class DirectoryException {
   const DirectoryException(String this.message);
   String toString() => "DirectoryException: $message";
   final String message;
 }