Use onClosed instead of onError in the WebSocket classes.

runtime/bin/websocket.dart

 // Copyright (c) 2012, 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.
 
 /**
  * The web socket protocol is implemented by a HTTP server handler
  * which can be instantiated like this:
  *
  *     WebSocketHandler wsHandler = new WebSocketHandler();
  *
@@ skipping 36 matching lines @@
    */
   void set onMessage(void callback(message));
 
   /**
    * Sets the callback to be called when the web socket connection is
    * closed.
    */
   void set onClosed(void callback(int status, String reason));
 
   /**
-   * Sets the callback to be called when the web socket connection
-   * encountered an error.
-   */
-  void set onError(void callback(e));
-
-  /**
    * Sends a message. The [message] must be a [:String:] a
    * [:List<int>:] or [:null:].
    */
   send(Object message);
 
   /**
    * Close the web socket connection. The default value for [status]
    * and [reason] are [:null:].
    */
   close([int status, String reason]);
@@ skipping 49 matching lines @@
    * Sets the callback to be called when the response object for the
    * opening handshake did not cause a web socket connection
    * upgrade. This will be called in case the response status code is
    * not 101 (Switching Protocols). If this callback is not set the
    * [:onError:] callback will be called if the server did not upgrade
    * the connection.
    */
   void set onNoUpgrade(void callback(HttpClientResponse response));
 
   /**
-   * Sets the callback to be called when the web socket connection
-   * encountered an error.
-   */
-  void set onError(void callback(e));
-
-  /**
    * Sends a message. The [message] must be a [:String:] or a
    * [:List<int>:]. To send an empty message use either an empty
    * [:String:] or an empty [:List<int>:]. [:null:] cannot be used.
    */
   send(message);
 
   /**
    * Close the web socket connection. The default value for [status]
    * and [reason] are [:null:].
    */
@@ skipping 130 matching lines @@
    */
   void send(data);
 }
 
 
 class WebSocketException implements Exception {
   const WebSocketException([String this.message = ""]);
   String toString() => "WebSocketException: $message";
   final String message;
 }