[TimeZoneMonitor] Decouple //content/browser/time_zone_monitor* to //device/.

content/browser/time_zone_monitor_mac.mm

-// 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.
-
-#import <Foundation/Foundation.h>
-
-#include "base/macros.h"
-#include "content/browser/time_zone_monitor.h"
-
-namespace content {
-
-class TimeZoneMonitorMac : public TimeZoneMonitor {
- public:
-  TimeZoneMonitorMac() : TimeZoneMonitor() {
-    NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
-    notification_observer_ =
-        [nc addObserverForName:NSSystemTimeZoneDidChangeNotification
-                        object:nil
-                         queue:nil
-                    usingBlock:^(NSNotification* notification) {
-                      NotifyClients();
-                    }];
-  }
-
-  ~TimeZoneMonitorMac() override {
-    NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
-    [nc removeObserver:notification_observer_];
-  }
-
- private:
-  id notification_observer_;
-
-  DISALLOW_COPY_AND_ASSIGN(TimeZoneMonitorMac);
-};
-
-// static
-std::unique_ptr<TimeZoneMonitor> TimeZoneMonitor::Create(
-    scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
-  return std::unique_ptr<TimeZoneMonitor>(new TimeZoneMonitorMac());
-}
-
-}  // namespace content