Revert of Add code to deal with serial device disconnection detection on Windows

device/serial/serial_io_handler.cc

 // Copyright 2014 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 "device/serial/serial_io_handler.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_util.h"
@@ skipping 26 matching lines @@
 
 void SerialIoHandler::Open(const std::string& port,
                            const serial::ConnectionOptions& options,
                            const OpenCompleteCallback& callback) {
   DCHECK(CalledOnValidThread());
   DCHECK(open_complete_.is_null());
   open_complete_ = callback;
   DCHECK(file_thread_task_runner_.get());
   DCHECK(ui_thread_task_runner_.get());
   MergeConnectionOptions(options);
-  port_ = port;
 
 #if defined(OS_CHROMEOS)
   chromeos::PermissionBrokerClient* client =
       chromeos::DBusThreadManager::Get()->GetPermissionBrokerClient();
   DCHECK(client) << "Could not get permission_broker client.";
   // PermissionBrokerClient should be called on the UI thread.
   ui_thread_task_runner_->PostTask(
       FROM_HERE, base::Bind(&chromeos::PermissionBrokerClient::OpenPath,
                             base::Unretained(client), port,
                             base::Bind(&SerialIoHandler::OnPathOpened, this,
@@ skipping 200 matching lines @@
 }
 
 void SerialIoHandler::QueueWriteCompleted(int bytes_written,
                                           serial::SendError error) {
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&SerialIoHandler::WriteCompleted, this, bytes_written, error));
 }
 
 }  // namespace device