Revert of Move throttling of background timers into the renderer scheduler

components/scheduler/child/scheduler_helper.h

 // Copyright 2015 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_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 #define COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 
 #include "base/time/tick_clock.h"
 #include "components/scheduler/base/task_queue_manager.h"
 #include "components/scheduler/base/task_queue_selector.h"
@@ skipping 65 matching lines @@
     virtual void OnUnregisterTaskQueue(
         const scoped_refptr<TaskQueue>& queue) = 0;
   };
 
   // Called once to set the Observer. This function is called on the main
   // thread. If |observer| is null, then no callbacks will occur.
   // Note |observer| is expected to outlive the SchedulerHelper.
   void SetObserver(Observer* observer);
 
   // Accessor methods.
-  RealTimeDomain* real_time_domain() const;
-  void RegisterTimeDomain(TimeDomain* time_domain);
-  void UnregisterTimeDomain(TimeDomain* time_domain);
+  const scoped_refptr<RealTimeDomain>& real_time_domain() const;
   const scoped_refptr<SchedulerTqmDelegate>& scheduler_tqm_delegate() const;
   bool GetAndClearSystemIsQuiescentBit();
 
   // Test helpers.
   void SetWorkBatchSizeForTesting(size_t work_batch_size);
   TaskQueueManager* GetTaskQueueManagerForTesting();
 
  private:
   friend class SchedulerHelperTest;
 
   base::ThreadChecker thread_checker_;
   scoped_refptr<SchedulerTqmDelegate> task_queue_manager_delegate_;
   scoped_ptr<TaskQueueManager> task_queue_manager_;
   scoped_refptr<TaskQueue> control_task_runner_;
   scoped_refptr<TaskQueue> control_after_wakeup_task_runner_;
   scoped_refptr<TaskQueue> default_task_runner_;
 
   Observer* observer_;  // NOT OWNED
   const char* tracing_category_;
   const char* disabled_by_default_tracing_category_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerHelper);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_