Fixes bug where clock button wasn't updating in response to a timezone

chrome/browser/chromeos/status/timezone_clock_updater.h

+// Copyright (c) 2011 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_STATUS_TIMEZONE_CLOCK_UPDATER_H_
+#define CHROME_BROWSER_CHROMEOS_STATUS_TIMEZONE_CLOCK_UPDATER_H_
+#pragma once
+
+#include "chrome/browser/chromeos/system/timezone_settings.h"
+
+class ClockMenuButton;
+
+// TimezoneClockUpdater is responsible for updating a ClockMenuButton when the
+// timezone changes.
+class TimezoneClockUpdater
+    : public chromeos::system::TimezoneSettings::Observer {
+ public:
+  explicit TimezoneClockUpdater(ClockMenuButton* button);
+  virtual ~TimezoneClockUpdater();
+
+  // TimezoneSettings::Observer overrides:
+  virtual void TimezoneChanged(const icu::TimeZone& timezone) OVERRIDE;
+
+ private:
+  ClockMenuButton* button_;
+
+  DISALLOW_COPY_AND_ASSIGN(TimezoneClockUpdater);
+};
+
+#endif  // CHROME_BROWSER_CHROMEOS_STATUS_TIMEZONE_CLOCK_UPDATER_H_