TaskScheduler: Change Sequence::PeekTask to Sequence::TakeTask.

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 100 matching lines @@
   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();
-  TaskTraits traits(sequence->PeekTask()->traits);
 
-  // Update the priority of |traits| so that the next task in |sequence| runs
-  // with the highest priority in |sequence| as opposed to the next task's
-  // specific priority.
-  traits.WithPriority(sort_key.priority());
+  // 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);
 }
 
 void TaskSchedulerImpl::OnDelayedRunTimeUpdated() {
   service_thread_->WakeUp();
 }
 
 }  // namespace internal
 }  // namespace base