Fix double-closing of handles in Windows EventHandler.

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 158 matching lines @@
   }
   return true;
 }
 
 
 void Handle::Close() {
   ScopedLock lock(this);
   if (!IsClosing()) {
     // Close the socket and set the closing state. This close method can be
     // called again if this socket has pending IO operations in flight.
-    ASSERT(handle_ != INVALID_HANDLE_VALUE);
     MarkClosing();
     // Perform handle type specific closing.
     DoClose();
   }
+  ASSERT(IsHandleClosed());
 }
 
 
 void Handle::DoClose() {
-  CloseHandle(handle_);
-  handle_ = INVALID_HANDLE_VALUE;
+  if (!IsHandleClosed()) {
+    CloseHandle(handle_);
+    handle_ = INVALID_HANDLE_VALUE;
+  }
 }
 
 
 bool Handle::HasPendingRead() {
   ScopedLock lock(this);
   return pending_read_ != NULL;
 }
 
 
 bool Handle::HasPendingWrite() {
@@ skipping 217 matching lines @@
 }
 
 
 void DirectoryWatchHandle::Stop() {
   ScopedLock lock(this);
   // Stop the outstanding read, so we can close the handle.
 
   if (pending_read_ != NULL) {
     CancelIoEx(handle(), pending_read_->GetCleanOverlapped());
     // Don't dispose of the buffer, as it will still complete (with length 0).
-    pending_read_ = NULL;
   }
 
-  CloseHandle(handle());
-  handle_ = (INVALID_HANDLE_VALUE);
+  DoClose();
 }
 
 
 void SocketHandle::HandleIssueError() {
   int error = WSAGetLastError();
   if (error == WSAECONNRESET) {
     HandleClosed(this);
   } else {
     HandleError(this);
   }
@@ skipping 921 matching lines @@
 
 
 void EventHandlerImplementation::Shutdown() {
   SendData(kShutdownId, 0, 0);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)