ChromeOS should have UTC timezone option.

chromeos/settings/timezone_settings.cc

 // 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.
 
 #include "chromeos/settings/timezone_settings.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
 #include "base/task_runner.h"
 #include "base/threading/worker_pool.h"
 #include "chromeos/settings/timezone_settings_helper.h"
 
+namespace chromeos {
+namespace system {
+const char kUTCTimezoneName[] = "Etc/GMT";
+}
+}
+
 namespace {
 
 // The filepath to the timezone file that symlinks to the actual timezone file.
 const char kTimezoneSymlink[] = "/var/lib/timezone/localtime";
 const char kTimezoneSymlink2[] = "/var/lib/timezone/localtime2";
 
 // The directory that contains all the timezone files. So for timezone
 // "US/Pacific", the actual timezone file is: "/usr/share/zoneinfo/US/Pacific"
 const char kTimezoneFilesDir[] = "/usr/share/zoneinfo/";
 
@@ skipping 35 matching lines @@
     "America/Santiago",
     "America/St_Johns",
     "America/Araguaina",
     "America/Argentina/Buenos_Aires",
     "America/Argentina/San_Luis",
     "America/Sao_Paulo",
     "America/Montevideo",
     "America/Godthab",
     "Atlantic/South_Georgia",
     "Atlantic/Cape_Verde",
+    chromeos::system::kUTCTimezoneName,
     "Atlantic/Azores",
     "Atlantic/Reykjavik",
     "Atlantic/St_Helena",
     "Africa/Casablanca",
     "Atlantic/Faroe",
     "Europe/Dublin",
     "Europe/Lisbon",
     "Europe/London",
     "Europe/Amsterdam",
     "Europe/Belgrade",
@@ skipping 374 matching lines @@
 
 // static
 base::string16 TimezoneSettings::GetTimezoneID(const icu::TimeZone& timezone) {
   icu::UnicodeString id;
   timezone.getID(id);
   return base::string16(id.getBuffer(), id.length());
 }
 
 }  // namespace system
 }  // namespace chromeos