Add a NetLog event for when sockets are closed.

net/socket/tcp_socket_win.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/socket/tcp_socket_win.h"
 
 #include <mstcpip.h>
 
 #include "base/callback_helpers.h"
 #include "base/logging.h"
@@ skipping 623 matching lines @@
 }
 
 bool TCPSocketWin::SetNoDelay(bool no_delay) {
   return DisableNagle(socket_, no_delay);
 }
 
 void TCPSocketWin::Close() {
   DCHECK(CalledOnValidThread());
 
   if (socket_ != INVALID_SOCKET) {
+    // Only log the close event if there's actually a socket to close.
+    net_log_.AddEvent(NetLog::EventType::TYPE_SOCKET_CLOSED);
+
     // Note: don't use CancelIo to cancel pending IO because it doesn't work
     // when there is a Winsock layered service provider.
 
     // In most socket implementations, closing a socket results in a graceful
     // connection shutdown, but in Winsock we have to call shutdown explicitly.
     // See the MSDN page "Graceful Shutdown, Linger Options, and Socket Closure"
     // at http://msdn.microsoft.com/en-us/library/ms738547.aspx
     shutdown(socket_, SD_SEND);
 
     // This cancels any pending IO.
@@ skipping 358 matching lines @@
   waiting_read_ = false;
   core_->read_iobuffer_ = NULL;
   core_->read_buffer_length_ = 0;
 
   DCHECK_NE(rv, ERR_IO_PENDING);
   base::ResetAndReturn(&read_callback_).Run(rv);
 }
 
 }  // namespace net