components: Cleanup class/struct fwd declarations

components/drive/job_scheduler.h

 // Copyright (c) 2012 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 COMPONENTS_DRIVE_JOB_SCHEDULER_H_
 #define COMPONENTS_DRIVE_JOB_SCHEDULER_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/id_map.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "components/drive/drive_uploader.h"
 #include "components/drive/job_list.h"
 #include "components/drive/job_queue.h"
 #include "components/drive/service/drive_service_interface.h"
 #include "net/base/network_change_notifier.h"
 
 class PrefService;
 
-namespace base {
-class SeqencedTaskRunner;
-}
-
 namespace drive {
 
 class EventLogger;
 
 // Priority of a job.  Higher values are lower priority.
 enum ContextType {
   USER_INITIATED,
   BACKGROUND,
   // Indicates the number of values of this enum.
   NUM_CONTEXT_TYPES,
@@ skipping 363 matching lines @@
 
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<JobScheduler> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(JobScheduler);
 };
 
 }  // namespace drive
 
 #endif  // COMPONENTS_DRIVE_JOB_SCHEDULER_H_