Separate the create and start phases in DelayedTaskManager.

base/task_scheduler/task_scheduler_impl.cc

Index: base/task_scheduler/task_scheduler_impl.cc
diff --git a/base/task_scheduler/task_scheduler_impl.cc b/base/task_scheduler/task_scheduler_impl.cc
index 01786493748a967f9901b206245d2bb5879f05c0..70c80054f621a398707331e8d12d8a07fd8c751f 100644
--- a/base/task_scheduler/task_scheduler_impl.cc
+++ b/base/task_scheduler/task_scheduler_impl.cc
@@ -186,14 +186,13 @@ void TaskSchedulerImpl::Initialize(
       base::MakeUnique<TaskTracker>();
 #endif
 
-  // Instantiate DelayedTaskManager. Needs to happen after starting the service
-  // thread to get its task_runner().
-  delayed_task_manager_ =
-      base::MakeUnique<DelayedTaskManager>(service_thread_.task_runner());
+  // Start DelayedTaskManager. Needs to happen after starting the service thread
+  // to get its task_runner().
+  delayed_task_manager_.Start(service_thread_.task_runner());
 
   single_thread_task_runner_manager_ =
       MakeUnique<SchedulerSingleThreadTaskRunnerManager>(
-          task_tracker_.get(), delayed_task_manager_.get());
+          task_tracker_.get(), &delayed_task_manager_);
   single_thread_task_runner_manager_->Start();
 
   // Callback invoked by workers to re-enqueue a sequence in the appropriate
@@ -228,7 +227,7 @@ void TaskSchedulerImpl::Initialize(
         name_ + kEnvironmentParams[environment_type].name_suffix,
         kEnvironmentParams[environment_type].priority_hint,
         re_enqueue_sequence_callback, task_tracker_.get(),
-        delayed_task_manager_.get());
+        &delayed_task_manager_);
     worker_pools_[environment_type]->Start(
         *worker_pool_params[environment_type]);
   }