Revert of ChromeOS: Per-user time zone: refactor tests first.

chrome/browser/chromeos/scoped_set_running_on_chromeos_for_testing.h

-// Copyright 2017 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_SCOPED_SET_RUNNING_ON_CHROMEOS_FOR_TESTING_H_
-#define CHROME_BROWSER_CHROMEOS_SCOPED_SET_RUNNING_ON_CHROMEOS_FOR_TESTING_H_
-
-#include <string>
-
-#include "base/time/time.h"
-
-namespace chromeos {
-
-// unit_tests must always reset status of modified global singletons,
-// otherwise later tests will fail, because they are run in the same process.
-//
-// This object resets LSB-Release to empty string on destruction, forcing
-// is_running_on_chromeos() to return false.
-class ScopedSetRunningOnChromeOSForTesting {
- public:
-  ScopedSetRunningOnChromeOSForTesting(const std::string& lsb_release,
-                                       const base::Time& lsb_release_time);
-  ~ScopedSetRunningOnChromeOSForTesting();
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ScopedSetRunningOnChromeOSForTesting);
-};
-
-}  // namespace chromeos
-
-#endif  //  CHROME_BROWSER_CHROMEOS_SCOPED_SET_RUNNING_ON_CHROMEOS_FOR_TESTING_H_