TaskScheduler: Remove OnMainExit from SchedulerWorkerThread::Delegate.

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 22 matching lines @@
  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 when the main function of the SchedulerWorkerThread exits.
-    virtual void OnMainExit() = 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 EnqueueSequence(scoped_refptr<Sequence> sequence) = 0;
   };
 
   // Creates a SchedulerWorkerThread with priority |thread_priority| that runs
@@ skipping 44 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_