Close 'accepted' sockets when listening socket is closed. Fixes raw_server_socket_cancel_test.

tests/standalone/io/raw_server_socket_cancel_test.dart

 // Copyright (c) 2013, 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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
 
 void testCancelResubscribeServerSocket(int socketCount, int backlog) {
   var acceptCount = 0;
   var doneCount = 0;
-  var closeCount = 0;
   var errorCount = 0;
   var earlyErrorCount = 0;
 
   ReceivePort port = new ReceivePort();
 
   RawServerSocket.bind("127.0.0.1", 0, backlog: backlog).then((server) {
     Expect.isTrue(server.port > 0);
 
     void checkDone() {
-      if (doneCount + earlyErrorCount == socketCount &&
-          closeCount + errorCount + earlyErrorCount == socketCount) {
+      if (doneCount + errorCount + earlyErrorCount == socketCount) {
         port.close();
       }
     }
 
     var subscription;
     subscription = server.listen((client) {
       client.writeEventsEnabled = false;
       client.listen((event) {
         switch(event) {
           case RawSocketEvent.READ:
             client.read();
             break;
           case RawSocketEvent.READ_CLOSED:
             client.shutdown(SocketDirection.SEND);
             break;
           case RawSocketEvent.WRITE:
             Expect.fail("No write event expected");
             break;
         }
       });
 
       if (++acceptCount == socketCount / 2) {
         // Cancel subscription and then attempt to resubscribe.
         subscription.cancel();
         Timer.run(() {
-          subscription = server.listen((_) {
-            // Server socket is closed on cancel, so no more events.
-            Expect.fail("Event after closed through cancel");
+          Expect.throws(() {
+            server.listen((_) {
+              // Server socket is closed on cancel, so no more events.
+              Expect.fail("Event after closed through cancel");
+            });
           });
         });
       }
     });
 
     // Connect a number of sockets.
     for (int i = 0; i < socketCount; i++) {
       RawSocket.connect("127.0.0.1", server.port).then((socket) {
+        bool done = false;
         var subscription;
         subscription = socket.listen((event) {
           switch(event) {
             case RawSocketEvent.READ:
               Expect.fail("No read event expected");
               break;
             case RawSocketEvent.READ_CLOSED:
-              closeCount++;
+              done = true;
+              doneCount++;
               checkDone();
               break;
             case RawSocketEvent.WRITE:
               // We don't care if this write succeeds, so we don't check
               // the return value (number of bytes written).
               socket.write([1,2,3]);
               socket.shutdown(SocketDirection.SEND);
               break;
           }
         },
         onDone: () {
-          doneCount++;
-          checkDone();
+          if (!done) {
+            doneCount++;
+            checkDone();
+          }
         },
         onError: (e) {
           // "Connection reset by peer" errors are handled here.
           errorCount++;
           checkDone();
-        });
+        }, cancelOnError: true);
       }).catchError((e) {
         // "Connection actively refused by host" errors are handled here.
         earlyErrorCount++;
         checkDone();
       });
     }
   });
 }
 
 void main() {
   testCancelResubscribeServerSocket(10, 20);
   testCancelResubscribeServerSocket(20, 5);
 }