Revert of Move throttling of background timers into the renderer scheduler

components/scheduler/base/task_queue_manager.h

Index: components/scheduler/base/task_queue_manager.h
diff --git a/components/scheduler/base/task_queue_manager.h b/components/scheduler/base/task_queue_manager.h
index f7090bd8dbc9016375a1429027db17deb97f65ce..f6af85453b2f412a5aaa209f432c2855b684f752 100644
--- a/components/scheduler/base/task_queue_manager.h
+++ b/components/scheduler/base/task_queue_manager.h
@@ -100,10 +100,12 @@
   const scoped_refptr<TaskQueueManagerDelegate>& delegate() const;
 
   // Time domains must be registered for the task queues to get updated.
-  void RegisterTimeDomain(TimeDomain* time_domain);
-  void UnregisterTimeDomain(TimeDomain* time_domain);
-
-  RealTimeDomain* real_time_domain() const { return real_time_domain_.get(); }
+  void RegisterTimeDomain(const scoped_refptr<TimeDomain>& time_domain);
+  void UnregisterTimeDomain(const scoped_refptr<TimeDomain>& time_domain);
+
+  const scoped_refptr<RealTimeDomain>& real_time_domain() const {
+    return real_time_domain_;
+  }
 
  private:
   friend class LazyNow;
@@ -174,8 +176,8 @@
   AsValueWithSelectorResult(bool should_run,
                             internal::TaskQueueImpl* selected_queue) const;
 
-  std::set<TimeDomain*> time_domains_;
-  scoped_ptr<RealTimeDomain> real_time_domain_;
+  std::set<scoped_refptr<TimeDomain>> time_domains_;
+  scoped_refptr<RealTimeDomain> real_time_domain_;
 
   std::set<scoped_refptr<internal::TaskQueueImpl>> queues_;
 
@@ -210,6 +212,7 @@
 
   Observer* observer_;  // NOT OWNED
   scoped_refptr<DeletionSentinel> deletion_sentinel_;
+  scoped_refptr<TimeDomain> time_domain_;
   base::WeakPtrFactory<TaskQueueManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueManager);