Change IllegalArgumentException to ArgumentError.

runtime/bin/websocket_impl.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.
 
 const String _webSocketGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 
 class _WebSocketMessageType {
   static const int NONE = 0;
   static const int BINARY = 1;
   static const int TEXT = 2;
@@ skipping 396 matching lines @@
       throw new WebSocketException("Connection closed");
     }
     List<int> data;
     int opcode;
     if (message !== null) {
       if (message is String) {
         opcode = _WebSocketOpcode.TEXT;
         data = _StringEncoders.encoder(Encoding.UTF_8).encodeString(message);
       } else {
         if (message is !List<int>) {
-          throw new IllegalArgumentException(message);
+          throw new ArgumentError(message);
         }
         opcode = _WebSocketOpcode.BINARY;
         data = message;
       }
     } else {
       opcode = _WebSocketOpcode.TEXT;
     }
     _sendFrame(opcode, data);
   }
 
@@ skipping 436 matching lines @@
 
 class _WebSocketCloseEvent implements CloseEvent {
   _WebSocketCloseEvent(this._wasClean, this._code, this._reason);
   bool get wasClean => _wasClean;
   int get code => _code;
   String get reason => _reason;
   bool _wasClean;
   int _code;
   String _reason;
 }