Modernize some TimeZoneMonitor code.

- Use std::make_unique() and "= default" in TimeZoneMonitorWin.
- Change a TimeZoneMonitorWin member from std::unique_ptr<T> to T.
- Get rid of DISALLOW_COPY_AND_ASSIGN() in TimeZoneMonitor.

Change-Id: I9dea9a1873cf8a04ad77ca3953aeeada0c74e8e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3119686
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#916522}

services/device/time_zone_monitor/time_zone_monitor.h

@@ -8,7 +8,6 @@
 #include <memory>
 #include <string>
 
-#include "base/macros.h"
 #include "base/strings/string_piece_forward.h"
 #include "base/threading/thread_checker.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
@@ -56,6 +55,8 @@ class TimeZoneMonitor : public device::mojom::TimeZoneMonitor {
   static std::unique_ptr<TimeZoneMonitor> Create(
       scoped_refptr<base::SequencedTaskRunner> file_task_runner);
 
+  TimeZoneMonitor(const TimeZoneMonitor&) = delete;
+  TimeZoneMonitor& operator=(const TimeZoneMonitor&) = delete;
   ~TimeZoneMonitor() override;
 
   void Bind(mojo::PendingReceiver<device::mojom::TimeZoneMonitor> receiver);
@@ -88,7 +89,6 @@ class TimeZoneMonitor : public device::mojom::TimeZoneMonitor {
 
   mojo::ReceiverSet<device::mojom::TimeZoneMonitor> receivers_;
   mojo::RemoteSet<device::mojom::TimeZoneMonitorClient> clients_;
-  DISALLOW_COPY_AND_ASSIGN(TimeZoneMonitor);
 };
 
 }  // namespace device

services/device/time_zone_monitor/time_zone_monitor_win.cc

@@ -23,14 +23,14 @@ class TimeZoneMonitorWin : public TimeZoneMonitor {
  public:
   TimeZoneMonitorWin()
       : TimeZoneMonitor(),
-        singleton_hwnd_observer_(new gfx::SingletonHwndObserver(
+        singleton_hwnd_observer_(
             base::BindRepeating(&TimeZoneMonitorWin::OnWndProc,
-                                base::Unretained(this)))),
+                                base::Unretained(this))),
         current_platform_timezone_(GetPlatformTimeZone()) {}
   TimeZoneMonitorWin(const TimeZoneMonitorWin&) = delete;
   TimeZoneMonitorWin& operator=(const TimeZoneMonitorWin&) = delete;
 
-  ~TimeZoneMonitorWin() override {}
+  ~TimeZoneMonitorWin() override = default;
 
  private:
   void OnWndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
@@ -85,7 +85,7 @@ class TimeZoneMonitorWin : public TimeZoneMonitor {
     pending_update_notification_tasks_ = false;
   }
 
-  std::unique_ptr<gfx::SingletonHwndObserver> singleton_hwnd_observer_;
+  gfx::SingletonHwndObserver singleton_hwnd_observer_;
   bool pending_update_notification_tasks_ = false;
   std::string current_platform_timezone_;
   base::WeakPtrFactory<TimeZoneMonitorWin> weak_ptr_factory_{this};
@@ -94,7 +94,7 @@ class TimeZoneMonitorWin : public TimeZoneMonitor {
 // static
 std::unique_ptr<TimeZoneMonitor> TimeZoneMonitor::Create(
     scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
-  return std::unique_ptr<TimeZoneMonitor>(new TimeZoneMonitorWin());
+  return std::make_unique<TimeZoneMonitorWin>();
 }
 
 }  // namespace device