TaskScheduler [12] Support SINGLE_THREADED in SchedulerThreadPool DO NOT SUBMIT

base/task_scheduler/scheduler_worker_thread.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_THREAD_H_
 #define BASE_TASK_SCHEDULER_SCHEDULER_WORKER_THREAD_H_
 
 #include <memory>
 
+#include "base/atomicops.h"
 #include "base/base_export.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/task_scheduler/priority_queue.h"
 #include "base/task_scheduler/scheduler_lock.h"
 #include "base/task_scheduler/scheduler_task_executor.h"
 #include "base/task_scheduler/sequence.h"
 #include "base/threading/platform_thread.h"
@@ skipping 56 matching lines @@
   // Destroying a SchedulerWorkerThread in production is not allowed; it is
   // always leaked. In tests, it can only be destroyed after JoinForTesting()
   // has returned.
   ~SchedulerWorkerThread() override;
 
   // Returns a SingleThreadTaskRunner whose PostTask invocations will result in
   // scheduling Tasks with |traits| on this worker thread.
   scoped_refptr<SingleThreadTaskRunner> CreateTaskRunnerWithTraits(
       const TaskTraits& traits);
 
+  // Returns the number of single-thread TaskRunners associated with this
+  // SchedulerWorkerThread.
+  size_t GetNumSingleThreadTaskRunners() const;
+
   // Wakes up this SchedulerWorkerThread if it wasn't already awake. After this
   // is called, this SchedulerWorkerThread will run Tasks from Sequences
   // returned by the GetWork() method of its delegate until it returns nullptr.
   void WakeUp();
 
   // Joins this SchedulerWorkerThread. If a Task is already running, it will be
   // allowed to complete its execution. This can only be called once.
   void JoinForTesting();
 
   // SchedulerTaskExecutor:
@@ skipping 11 matching lines @@
   void ThreadMain() override;
 
   bool ShouldExitForTesting() const;
 
   // Platform thread managed by this SchedulerWorkerThread.
   PlatformThreadHandle thread_handle_;
 
   // Event signaled to wake up this SchedulerWorkerThread.
   WaitableEvent wake_up_event_;
 
+  // Number of single-thread TaskRunners associated with this
+  // SchedulerWorkerThread.
+  base::subtle::Atomic32 num_single_thread_task_runners_;
+
   // PriorityQueue for Tasks/Sequences posted through SingleThreadTaskRunners
   // returned by CreateTaskRunnerWithTraits.
   PriorityQueue single_threaded_priority_queue_;
 
   Delegate* const delegate_;
   TaskTracker* const task_tracker_;
   DelayedTaskManager* const delayed_task_manager_;
 
   // Synchronizes access to |should_exit_for_testing_|.
   mutable SchedulerLock should_exit_for_testing_lock_;
 
   // True once JoinForTesting() has been called.
   bool should_exit_for_testing_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerWorkerThread);
 };
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_TASK_SCHEDULER_SCHEDULER_WORKER_THREAD_H_