Revert of Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

content/browser/service_worker/service_worker_database.h

 // 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.
 
 #ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/optional.h"
 #include "base/sequence_checker.h"
 #include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "content/common/origin_trials/trial_token_validator.h"
 #include "content/common/service_worker/service_worker_status_code.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "url/gurl.h"
 #include "url/origin.h"
 
-namespace tracked_objects {
-class Location;
-}
-
 namespace leveldb {
 class DB;
 class Env;
 class Status;
 class WriteBatch;
 }
 
 namespace content {
 
 // Class to persist serviceworker registration data in a database.
@@ skipping 357 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest,
                            UserData_UninitializedDatabase);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, DestroyDatabase);
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerDatabase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_