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

chrome/browser/chromeos/login/users/supervised_user_manager_impl.cc

 // 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.
 
 #include "chrome/browser/chromeos/login/users/supervised_user_manager_impl.h"
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
@@ skipping 116 matching lines @@
   registry->RegisterDictionaryPref(kSupervisedUserPasswordRevision);
 
   registry->RegisterDictionaryPref(kSupervisedUserNeedPasswordUpdate);
   registry->RegisterDictionaryPref(kSupervisedUserIncompleteKey);
 }
 
 SupervisedUserManagerImpl::SupervisedUserManagerImpl(
     ChromeUserManagerImpl* owner)
     : owner_(owner), cros_settings_(CrosSettings::Get()) {
   // SupervisedUserManager instance should be used only on UI thread.
-  // (or in unit_tests)
-  if (base::ThreadTaskRunnerHandle::IsSet())
-    DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   authentication_.reset(new SupervisedUserAuthentication(this));
 }
 
 SupervisedUserManagerImpl::~SupervisedUserManagerImpl() {
 }
 
 std::string SupervisedUserManagerImpl::GenerateUserId() {
   int counter = g_browser_process->local_state()->
       GetInteger(kSupervisedUsersNextId);
   std::string id;
@@ skipping 376 matching lines @@
 }
 
 void SupervisedUserManagerImpl::ConfigureSyncWithToken(
     Profile* profile,
     const std::string& token) {
   if (!token.empty())
     SupervisedUserServiceFactory::GetForProfile(profile)->InitSync(token);
 }
 
 }  // namespace chromeos