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

device/serial/serial_io_handler_win.cc

Index: device/serial/serial_io_handler_win.cc
diff --git a/device/serial/serial_io_handler_win.cc b/device/serial/serial_io_handler_win.cc
index c814755d158fc11464a0f19e2114ecd5030dbefb..cd1045107fe746e285d1bf422297236228339638 100644
--- a/device/serial/serial_io_handler_win.cc
+++ b/device/serial/serial_io_handler_win.cc
@@ -2,17 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <windows.h>
+
 #include "device/serial/serial_io_handler_win.h"
-
-#include <windows.h>
-#include <setupapi.h>
-
-#include "base/bind.h"
-#include "base/scoped_observer.h"
-#include "base/threading/thread_checker.h"
-#include "device/core/device_info_query_win.h"
-#include "device/core/device_monitor_win.h"
-#include "third_party/re2/re2/re2.h"
 
 namespace device {
 
@@ -138,12 +130,6 @@
   }
 }
 
-// Searches for the COM port in the device's friendly name, assigns its value to
-// com_port, and returns whether the operation was successful.
-bool GetCOMPort(const std::string friendly_name, std::string* com_port) {
-  return RE2::PartialMatch(friendly_name, ".* \\((COM[0-9]+)\\)", com_port);
-}
-
 }  // namespace
 
 // static
@@ -153,81 +139,6 @@
   return new SerialIoHandlerWin(file_thread_task_runner, ui_thread_task_runner);
 }
 
-class SerialIoHandlerWin::UiThreadHelper : 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()); }
-
-  static void Start(UiThreadHelper* self) {
-    self->thread_checker_.DetachFromThread();
-    DeviceMonitorWin* device_monitor = DeviceMonitorWin::GetForAllInterfaces();
-    if (device_monitor)
-      self->device_observer_.Add(device_monitor);
-  }
-
- private:
-  // DeviceMonitorWin::Observer
-  void OnDeviceRemoved(const GUID& class_guid,
-                       const std::string& device_path) override {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    io_thread_task_runner_->PostTask(
-        FROM_HERE, base::Bind(&SerialIoHandlerWin::OnDeviceRemoved, io_handler_,
-                              device_path));
-  }
-
-  base::ThreadChecker thread_checker_;
-  ScopedObserver<DeviceMonitorWin, DeviceMonitorWin::Observer> device_observer_;
-
-  // This weak pointer is only valid when checked on this task runner.
-  base::WeakPtr<SerialIoHandlerWin> io_handler_;
-  scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner_;
-
-  DISALLOW_COPY_AND_ASSIGN(UiThreadHelper);
-};
-
-void SerialIoHandlerWin::OnDeviceRemoved(const std::string& device_path) {
-  DCHECK(CalledOnValidThread());
-
-  DeviceInfoQueryWin device_info_query;
-  if (!device_info_query.device_info_list_valid()) {
-    DVPLOG(1) << "Failed to create a device information set";
-    return;
-  }
-
-  // This will add the device so we can query driver info.
-  if (!device_info_query.AddDevice(device_path.c_str())) {
-    DVPLOG(1) << "Failed to get device interface data for " << device_path;
-    return;
-  }
-
-  if (!device_info_query.GetDeviceInfo()) {
-    DVPLOG(1) << "Failed to get device info for " << device_path;
-    return;
-  }
-
-  std::string friendly_name;
-  if (!device_info_query.GetDeviceStringProperty(SPDRP_FRIENDLYNAME,
-                                                 &friendly_name)) {
-    DVPLOG(1) << "Failed to get device service property";
-    return;
-  }
-
-  std::string com_port;
-  if (!GetCOMPort(friendly_name, &com_port)) {
-    DVPLOG(1) << "Failed to get port name from \"" << friendly_name << "\".";
-    return;
-  }
-
-  if (port() == com_port)
-    CancelRead(serial::RECEIVE_ERROR_DISCONNECTED);
-}
-
 bool SerialIoHandlerWin::PostOpen() {
   DCHECK(!comm_context_);
   DCHECK(!read_context_);
@@ -247,13 +158,6 @@
   write_context_.reset(new base::MessageLoopForIO::IOContext());
   write_context_->handler = this;
   memset(&write_context_->overlapped, 0, sizeof(write_context_->overlapped));
-
-  scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner =
-      base::ThreadTaskRunnerHandle::Get();
-  helper_ =
-      new UiThreadHelper(weak_factory_.GetWeakPtr(), io_thread_task_runner);
-  ui_thread_task_runner()->PostTask(
-      FROM_HERE, base::Bind(&UiThreadHelper::Start, helper_));
 
   // A ReadIntervalTimeout of MAXDWORD will cause async reads to complete
   // immediately with any data that's available, even if there is none.
@@ -367,11 +271,10 @@
     scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner)
     : SerialIoHandler(file_thread_task_runner, ui_thread_task_runner),
       event_mask_(0),
-      is_comm_pending_(false),
-      weak_factory_(this) {}
+      is_comm_pending_(false) {
+}
 
 SerialIoHandlerWin::~SerialIoHandlerWin() {
-  ui_thread_task_runner()->DeleteSoon(FROM_HERE, helper_);
 }
 
 void SerialIoHandlerWin::OnIOCompleted(