Followup Feedback on https://codereview.chromium.org/2726073002/

base/task_scheduler/scheduler_single_thread_task_runner_manager.cc

 // Copyright 2017 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/scheduler_single_thread_task_runner_manager.h"
 
 #include <algorithm>
 #include <memory>
 #include <string>
 
@@ skipping 211 matching lines @@
   DCHECK(task_tracker_);
   DCHECK(delayed_task_manager_);
 }
 
 SchedulerSingleThreadTaskRunnerManager::
     ~SchedulerSingleThreadTaskRunnerManager() {
 #if DCHECK_IS_ON()
   size_t workers_unregistered_during_join =
       subtle::NoBarrier_Load(&workers_unregistered_during_join_);
   DCHECK_EQ(workers_unregistered_during_join, workers_.size())
-      << "There cannot be outstanding SingleThreadTaskRunners upon destruction"
+      << "There cannot be outstanding SingleThreadTaskRunners upon destruction "
          "of SchedulerSingleThreadTaskRunnerManager or the Task Scheduler";
 #endif
 }
 
 scoped_refptr<SingleThreadTaskRunner>
 SchedulerSingleThreadTaskRunnerManager::CreateSingleThreadTaskRunnerWithTraits(
     const TaskTraits& traits) {
   size_t index = worker_pool_index_for_traits_callback_.Run(traits);
   DCHECK_LT(index, worker_pool_params_vector_.size());
   return new SchedulerSingleThreadTaskRunner(
@@ skipping 56 matching lines @@
                      });
     DCHECK(worker_iter != workers_.end());
     worker_to_destroy = std::move(*worker_iter);
     workers_.erase(worker_iter);
   }
   worker_to_destroy->Cleanup();
 }
 
 }  // namespace internal
 }  // namespace base