TaskScheduler [11] Support ExecutionMode::SINGLE_THREADED.

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/base_export.h"
@@ skipping 19 matching lines @@
 //
 // This class is thread-safe.
 class BASE_EXPORT SchedulerWorkerThread : public PlatformThread::Delegate {
  public:
   // Delegate interface for SchedulerWorkerThread. The methods are always called
   // from the thread managed by the SchedulerWorkerThread instance.
   class Delegate {
    public:
     virtual ~Delegate() = default;
 
-    // Called when the main function of the SchedulerWorkerThread enters.
-    virtual void OnMainEntry() = 0;
+    // Called by |worker_thread| when it enters its main function.
+    virtual void OnMainEntry(SchedulerWorkerThread* worker_thread) = 0;
 
     // Called by |worker_thread| to get a Sequence from which to run a Task.
     virtual scoped_refptr<Sequence> GetWork(
         SchedulerWorkerThread* worker_thread) = 0;
 
     // Called when |sequence| isn't empty after the SchedulerWorkerThread pops a
     // Task from it. |sequence| is the last Sequence returned by GetWork().
     virtual void ReEnqueueSequence(scoped_refptr<Sequence> sequence) = 0;
   };
 
   // Creates a SchedulerWorkerThread with priority |thread_priority| that runs
   // Tasks from Sequences returned by |delegate|. |task_tracker| is used to
   // handle shutdown behavior of Tasks. Returns nullptr if creating the
   // underlying platform thread fails.
   static std::unique_ptr<SchedulerWorkerThread> Create(
       ThreadPriority thread_priority,
       std::unique_ptr<Delegate> delegate,
       TaskTracker* task_tracker);
 
   // 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;
 
   // 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();
 
+  SchedulerWorkerThread::Delegate* delegate() { return delegate_.get(); }
+
   // 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();
 
  private:
   SchedulerWorkerThread(ThreadPriority thread_priority,
                         std::unique_ptr<Delegate> delegate,
                         TaskTracker* task_tracker);
 
   // PlatformThread::Delegate:
@@ skipping 16 matching lines @@
   // 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_