Revert of Redirect the MessageLoop's task runner to the renderer scheduler

components/scheduler/child/webthread_impl_for_worker_scheduler.h

 // Copyright 2015 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 COMPONENTS_SCHEDULER_CHILD_WEBTHREAD_IMPL_FOR_WORKER_SCHEDULER_H_
 #define COMPONENTS_SCHEDULER_CHILD_WEBTHREAD_IMPL_FOR_WORKER_SCHEDULER_H_
 
 #include "components/scheduler/child/task_queue_manager.h"
 #include "components/scheduler/child/webthread_base.h"
 
@@ skipping 28 matching lines @@
   // base::MessageLoop::DestructionObserver implementation.
   void WillDestroyCurrentMessageLoop() override;
 
  private:
   void AddTaskObserverInternal(
       base::MessageLoop::TaskObserver* observer) override;
   void RemoveTaskObserverInternal(
       base::MessageLoop::TaskObserver* observer) override;
 
   void InitOnThread(base::WaitableEvent* completion);
-  void ShutdownOnThread(base::WaitableEvent* completion);
 
   scoped_ptr<base::Thread> thread_;
   scoped_ptr<scheduler::WorkerScheduler> worker_scheduler_;
   scoped_ptr<scheduler::WebSchedulerImpl> web_scheduler_;
-  scoped_refptr<base::SingleThreadTaskRunner> thread_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_refptr<scheduler::SingleThreadIdleTaskRunner> idle_task_runner_;
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_CHILD_WEBTHREAD_IMPL_FOR_WORKER_SCHEDULER_H_