WILL BE MERGED Change Ownership of Sequence to the Single Thread SchedulerWorker Delegate

base/task_scheduler/scheduler_worker.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_H_
 #define BASE_TASK_SCHEDULER_SCHEDULER_WORKER_H_
 
 #include <memory>
 
 #include "base/base_export.h"
@@ skipping 67 matching lines @@
     // When true is returned:
     // - The next WakeUp() could be more costly due to new thread creation.
     // - The worker will take this as a signal that it can detach, but it is not
     //   obligated to do so.
     virtual bool CanDetach(SchedulerWorker* worker) = 0;
 
     // Called by a thread before it detaches. This method is not allowed to
     // acquire a SchedulerLock because it is called within the scope of another
     // SchedulerLock.
     virtual void OnDetach() = 0;
+
+    // Called by a thread right before the main function exits.
+    virtual void OnMainExit() {}
   };
 
   enum class InitialState { ALIVE, DETACHED };
 
   // Creates a SchedulerWorker that runs Tasks from Sequences returned by
   // |delegate|. |priority_hint| is the preferred thread priority; the actual
   // thread priority depends on shutdown state and platform capabilities.
   // |task_tracker| is used to handle shutdown behavior of Tasks. If
   // |worker_state| is DETACHED, the thread will be created upon a WakeUp().
   // Returns nullptr if creating the underlying platform thread fails during
@@ skipping 91 matching lines @@
   // Set once JoinForTesting() has been called.
   AtomicFlag join_called_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerWorker);
 };
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_TASK_SCHEDULER_SCHEDULER_WORKER_H_