Add a timezone utility file to base/.

base/i18n/timezone.h

+// Copyright 2013 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 BASE_I18N_TIMEZONE_H_
+#define BASE_I18N_TIMEZONE_H_
+
+#include <string>
+
+#include "base/i18n/base_i18n_export.h"
+
+namespace base {
+
+// Checks the system timezone and turns it into a two-character ASCII country
+// code. If this fails for some reason (for example, it will always fail on
+// Android), it will return an empty string.
+BASE_I18N_EXPORT std::string CountryCodeForCurrentTimezone();
+
+}  // namespace base
+
+#endif  // BASE_TIME_TIMEZONE_H_