Second round of cleanups for new optional parameter semantics.

samples/chat/chat_server_lib.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.
 
 #library("chat_server");
 #import("dart:io");
 #import("dart:isolate");
 #import("dart:json");
 #import("dart:math");
 
@@ skipping 206 matching lines @@
   Map<String, Function> _callbacks;
 }
 
 
 class ChatServerCommand {
   static const START = 0;
   static const STOP = 1;
 
   ChatServerCommand.start(String this._host,
                           int this._port,
-                          [int backlog = 5,
-                           bool logging = false])
+                          {int backlog: 5,
+                           bool logging: false})
       : _command = START, _backlog = backlog, _logging = logging;
   ChatServerCommand.stop() : _command = STOP;
 
   bool get isStart => _command == START;
   bool get isStop => _command == STOP;
 
   String get host => _host;
   int get port => _port;
   bool get logging => _logging;
   int get backlog => _backlog;
@@ skipping 445 matching lines @@
     }
   }
 
   int _timeRange;
   List<int> _buckets;
   int _currentBucket;
   int _currentBucketTime;
   num _bucketTimeRange;
   int _sum;
 }