Rename blahHandler to onBlah throughout dart:io.

tests/standalone/src/SocketManyConnectionsTest.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 //
 // Test creating a large number of socket connections.
 
 #library("SocketManyConnectionsTest");
 #import("dart:io");
 #import("dart:isolate");
 #source("TestingServer.dart");
 
@@ skipping 20 matching lines @@
         for (int i = 0; i < CONNECTIONS; i++) {
           _sockets[i].close();
         }
         shutdown();
       }
     }
 
     for (int i = 0; i < CONNECTIONS; i++) {
       _sockets[i] = new Socket(TestingServer.HOST, _port);
       if (_sockets[i] !== null) {
-        _sockets[i].connectHandler = connectHandler;
+        _sockets[i].onConnect = connectHandler;
       } else {
         Expect.fail("socket creation failed");
       }
     }
   }
 
   void start() {
     _receivePort.receive((var message, SendPort replyTo) {
       _port = message;
       run();
@@ skipping 21 matching lines @@
     void closeHandler() {
       connection.close();
     }
 
     void errorHandler() {
       print("Socket error");
       connection.close();
     }
 
     _connections++;
-    connection.closeHandler = closeHandler;
-    connection.errorHandler = errorHandler;
+    connection.onClosed = closeHandler;
+    connection.onError = errorHandler;
   }
 
   int _connections = 0;
 }
 
 main() {
   SocketManyConnectionsTest test = new SocketManyConnectionsTest.start();
 }