Don't act on return-token commands on Windows.

runtime/bin/eventhandler_win.cc

 // 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.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/eventhandler.h"
 
 #include <winsock2.h>  // NOLINT
@@ skipping 927 matching lines @@
 
 
 void EventHandlerImplementation::HandleInterrupt(InterruptMessage* msg) {
   if (msg->id == kTimeoutId) {
     // Change of timeout request. Just set the new timeout and port as the
     // completion thread will use the new timeout value for its next wait.
     timeout_queue_.UpdateTimeout(msg->dart_port, msg->data);
   } else if (msg->id == kShutdownId) {
     shutdown_ = true;
   } else {
+    // No tokens to return on Windows.
+    if ((msg->data & (1 << kReturnTokenCommand)) != 0) return;
     Handle* handle = reinterpret_cast<Handle*>(msg->id);
     ASSERT(handle != NULL);
     if (handle->is_listen_socket()) {
       ListenSocket* listen_socket =
           reinterpret_cast<ListenSocket*>(handle);
       listen_socket->EnsureInitialized(this);
       listen_socket->SetPortAndMask(msg->dart_port, msg->data);
 
       Handle::ScopedLock lock(listen_socket);
 
@@ skipping 329 matching lines @@
 
 
 void EventHandlerImplementation::Shutdown() {
   SendData(kShutdownId, 0, 0);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)