TaskScheduler: Always remove SchedulerWorker from idle stack on wake up.

base/task_scheduler/scheduler_worker_pool_impl.h

 // 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.
 
 #ifndef BASE_TASK_SCHEDULER_SCHEDULER_WORKER_POOL_IMPL_H_
 #define BASE_TASK_SCHEDULER_SCHEDULER_WORKER_POOL_IMPL_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 96 matching lines @@
                               io_restriction,
                           const TimeDelta& suggested_reclaim_time,
                           TaskTracker* task_tracker,
                           DelayedTaskManager* delayed_task_manager);
 
   bool Initialize(
       ThreadPriority priority_hint,
       size_t max_threads,
       const ReEnqueueSequenceCallback& re_enqueue_sequence_callback);
 
-  // Wakes up the last worker from this worker pool to go idle, if any.
+  // Wakes up |worker| and removes it from the idle stack.

[robliao, 2016/10/13 17:38:40]

Leave both of these comments like they were before. The idle stack is an
implementation detail.

Instead, I would discuss the invariant that the idle stack only contains idle
workers below.

[fdoray, 2016/10/13 18:46:55]

Done.

+  void WakeUpWorker(SchedulerWorker* worker);
+
+  // Wakes up and removes from the idle stack the last worker from this worker
+  // pool to go idle, if any.
   void WakeUpOneWorker();
 
   // Adds |worker| to |idle_workers_stack_|.
   void AddToIdleWorkersStack(SchedulerWorker* worker);
 
   // Peeks from |idle_workers_stack_|.
   const SchedulerWorker* PeekAtIdleWorkersStack() const;
 
   // Removes |worker| from |idle_workers_stack_|.
   void RemoveFromIdleWorkersStack(SchedulerWorker* worker);
@@ skipping 68 matching lines @@
   TaskTracker* const task_tracker_;
   DelayedTaskManager* const delayed_task_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerWorkerPoolImpl);
 };
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_TASK_SCHEDULER_SCHEDULER_WORKER_POOL_IMPL_H_