Separate the create and start phases in SchedulerWorkerPoolImpl.

base/task_scheduler/task_scheduler_impl.cc

 // Copyright 2016 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.
 
 #include "base/task_scheduler/task_scheduler_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 234 matching lines @@
   // PriorityQueue.
   const SchedulerWorkerPoolImpl::ReEnqueueSequenceCallback
       re_enqueue_sequence_callback =
           Bind(&TaskSchedulerImpl::ReEnqueueSequenceCallback, Unretained(this));
 
   // Start worker pools.
   for (const auto& worker_pool_params : worker_pool_params_vector) {
     // Passing pointers to objects owned by |this| to
     // SchedulerWorkerPoolImpl::Create() is safe because a TaskSchedulerImpl
     // can't be deleted before all its worker pools have been joined.
-    worker_pools_.push_back(SchedulerWorkerPoolImpl::Create(
-        worker_pool_params, re_enqueue_sequence_callback, task_tracker_.get(),
+    worker_pools_.push_back(MakeUnique<SchedulerWorkerPoolImpl>(
+        worker_pool_params.name(), worker_pool_params.priority_hint(),
+        re_enqueue_sequence_callback, task_tracker_.get(),
         delayed_task_manager_.get()));
-    CHECK(worker_pools_.back());
+    worker_pools_.back()->Start(worker_pool_params);
   }
 }
 
 SchedulerWorkerPoolImpl* TaskSchedulerImpl::GetWorkerPoolForTraits(
     const TaskTraits& traits) const {
   const size_t index = worker_pool_index_for_traits_callback_.Run(traits);
   DCHECK_LT(index, worker_pools_.size());
   return worker_pools_[index].get();
 }
 
 void TaskSchedulerImpl::ReEnqueueSequenceCallback(
     scoped_refptr<Sequence> sequence) {
   DCHECK(sequence);
 
   const SequenceSortKey sort_key = sequence->GetSortKey();
 
   // The next task in |sequence| should run in a worker pool suited for its
   // traits, except for the priority which is adjusted to the highest priority
   // in |sequence|.
   const TaskTraits traits =
       sequence->PeekTaskTraits().WithPriority(sort_key.priority());
 
   GetWorkerPoolForTraits(traits)->ReEnqueueSequence(std::move(sequence),
                                                     sort_key);
 }
 
 }  // namespace internal
 }  // namespace base