Consistently use setters to set event handlers in native APIs.

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 exists();
+  bool existsSync();
 
   /**
    * Creates the directory with this name if it does not exist.
    * Throw an exception if the directory already exists.
    */
-  void create();
+  void createSync();
 
   /**
    * Deletes the directory with this name. Throws an exception
    * if the directory is not empty or if deletion failed.
    */
-  void delete();
+  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
    * the listing operation is recursive, the error handler is called
    * if a subdirectory cannot be opened for listing.
    */
   void list([bool recursive]);
 
   /**
    * Sets the directory handler that is called for all directories
    * during listing operations. The directory handler is called with
    * the full path of the directory.
    */
-  void setDirHandler(void dirHandler(String dir));
+  void set dirHandler(void dirHandler(String dir));
 
   /**
    * Sets the file handler that is called for all files during listing
    * operations. The file handler is called with the full path of the
    * file.
    */
-  void setFileHandler(void fileHandler(String file));
+  void set fileHandler(void fileHandler(String file));
 
   /**
    * Set the done 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 setDoneHandler(void doneHandler(bool completed));
+  void set doneHandler(void doneHandler(bool completed));
 
   /**
    * Sets the error handler that is called on error listing
    * directories.
    */
-  void setErrorHandler(void errorHandler(String error));
+  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;
 }