Revert of Delete base/prefs and update callers to use components.

components/drive/file_system/operation_test_base.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 "components/drive/file_system/operation_test_base.h"
 
+#include "base/prefs/testing_pref_service.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "components/drive/change_list_loader.h"
 #include "components/drive/event_logger.h"
 #include "components/drive/fake_free_disk_space_getter.h"
 #include "components/drive/file_cache.h"
 #include "components/drive/file_change.h"
 #include "components/drive/file_system/operation_delegate.h"
 #include "components/drive/job_scheduler.h"
 #include "components/drive/resource_metadata.h"
 #include "components/drive/service/fake_drive_service.h"
 #include "components/drive/service/test_util.h"
-#include "components/prefs/testing_pref_service.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_utils.h"
 #include "google_apis/drive/test_util.h"
 
 namespace drive {
 namespace file_system {
 
 OperationTestBase::LoggingDelegate::LoggingDelegate() {
 }
 
@@ skipping 157 matching lines @@
 FileError OperationTestBase::CheckForUpdates() {
   FileError error = FILE_ERROR_FAILED;
   change_list_loader_->CheckForUpdates(
       google_apis::test_util::CreateCopyResultCallback(&error));
   content::RunAllBlockingPoolTasksUntilIdle();
   return error;
 }
 
 }  // namespace file_system
 }  // namespace drive