Change handling of accepting socket connections

tests/standalone/src/EchoServerStreamTest.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.
 //
 // Echo server test program to test socket streams.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
@@ skipping 121 matching lines @@
   Socket _socket;
   List<int> _buffer;
   int _messages;
 }
 
 
 class EchoServer extends TestingServer {
 
   static final int MSGSIZE = EchoServerGame.MSGSIZE;
 
-  void connectionHandler() {
-    Socket _client;
+  void connectionHandler(Socket connection) {
     InputStream inputStream;
     List<int> buffer = new List<int>(MSGSIZE);
     int offset = 0;
 
     void dataReceived() {
       SocketOutputStream outputStream;
       int bytesRead;
-      outputStream = _client.outputStream;
+      outputStream = connection.outputStream;
       bytesRead = inputStream.readInto(buffer, offset, MSGSIZE - offset);
       if (bytesRead > 0) {
         offset += bytesRead;
         for (int i = 0; i < offset; i++) {
           Expect.equals(EchoServerGame.FIRSTCHAR + i, buffer[i]);
         }
         if (offset == MSGSIZE) {
           outputStream.write(buffer);
           outputStream.close();
         }
       }
     }
 
     void errorHandler() {
       Expect.fail("Socket error");
     }
 
-    _client = _server.accept();
-    inputStream = _client.inputStream;
+    inputStream = connection.inputStream;
     inputStream.dataHandler = dataReceived;
-    _client.errorHandler = errorHandler;
+    connection.errorHandler = errorHandler;
   }
 }
 
 main() {
   EchoServerGame echoServerGame = new EchoServerGame.start();
 }