Make SerialIoHandlerWin::UiThreadHelper final.

device/serial/serial_io_handler_win.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_win.h"
 
 #include <windows.h>
 #include <setupapi.h>
 
 #include "base/bind.h"
@@ skipping 135 matching lines @@
 
 }  // namespace
 
 // static
 scoped_refptr<SerialIoHandler> SerialIoHandler::Create(
     scoped_refptr<base::SingleThreadTaskRunner> file_thread_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner) {
   return new SerialIoHandlerWin(file_thread_task_runner, ui_thread_task_runner);
 }
 
-class SerialIoHandlerWin::UiThreadHelper : public DeviceMonitorWin::Observer {
+class SerialIoHandlerWin::UiThreadHelper final
+    : public DeviceMonitorWin::Observer {
  public:
   UiThreadHelper(
       base::WeakPtr<SerialIoHandlerWin> io_handler,
       scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner)
       : device_observer_(this),
         io_handler_(io_handler),
         io_thread_task_runner_(io_thread_task_runner) {}
 
   ~UiThreadHelper() { DCHECK(thread_checker_.CalledOnValidThread()); }
 
@@ skipping 194 matching lines @@
   }
   return true;
 }
 
 SerialIoHandlerWin::SerialIoHandlerWin(
     scoped_refptr<base::SingleThreadTaskRunner> file_thread_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner)
     : SerialIoHandler(file_thread_task_runner, ui_thread_task_runner),
       event_mask_(0),
       is_comm_pending_(false),
+      helper_(nullptr),
       weak_factory_(this) {}
 
 SerialIoHandlerWin::~SerialIoHandlerWin() {
   ui_thread_task_runner()->DeleteSoon(FROM_HERE, helper_);
 }
 
 void SerialIoHandlerWin::OnIOCompleted(
     base::MessageLoopForIO::IOContext* context,
     DWORD bytes_transferred,
     DWORD error) {
@@ skipping 150 matching lines @@
 std::string SerialIoHandler::MaybeFixUpPortName(const std::string& port_name) {
   // For COM numbers less than 9, CreateFile is called with a string such as
   // "COM1". For numbers greater than 9, a prefix of "\\\\.\\" must be added.
   if (port_name.length() > std::string("COM9").length())
     return std::string("\\\\.\\").append(port_name);
 
   return port_name;
 }
 
 }  // namespace device