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

components/scheduler/child/scheduler_task_runner_delegate_impl.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_SCHEDULER_TASK_RUNNER_DELEGATE_IMPL_H_
-#define COMPONENTS_SCHEDULER_CHILD_SCHEDULER_TASK_RUNNER_DELEGATE_IMPL_H_
-
-#include "base/message_loop/message_loop.h"
-#include "components/scheduler/child/scheduler_task_runner_delegate.h"
-#include "components/scheduler/scheduler_export.h"
-
-namespace scheduler {
-
-class SCHEDULER_EXPORT SchedulerTaskRunnerDelegateImpl
-    : public SchedulerTaskRunnerDelegate {
- public:
-  // |message_loop| is not owned and must outlive the lifetime of this object.
-  static scoped_refptr<SchedulerTaskRunnerDelegateImpl> Create(
-      base::MessageLoop* message_loop);
-
-  // SchedulerTaskRunnerDelegate implementation
-  void SetDefaultTaskRunner(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner) override;
-  void RestoreDefaultTaskRunner() override;
-  bool PostDelayedTask(const tracked_objects::Location& from_here,
-                       const base::Closure& task,
-                       base::TimeDelta delay) override;
-  bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
-                                  const base::Closure& task,
-                                  base::TimeDelta delay) override;
-  bool RunsTasksOnCurrentThread() const override;
-  bool IsNested() const override;
-  void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer) override;
-  void RemoveTaskObserver(
-      base::MessageLoop::TaskObserver* task_observer) override;
-
- protected:
-  ~SchedulerTaskRunnerDelegateImpl() override;
-
- private:
-  explicit SchedulerTaskRunnerDelegateImpl(base::MessageLoop* message_loop);
-
-  // Not owned.
-  base::MessageLoop* message_loop_;
-  scoped_refptr<SingleThreadTaskRunner> message_loop_task_runner_;
-
-  DISALLOW_COPY_AND_ASSIGN(SchedulerTaskRunnerDelegateImpl);
-};
-
-}  // namespace scheduler
-
-#endif  // COMPONENTS_SCHEDULER_CHILD_SCHEDULER_TASK_RUNNER_DELEGATE_IMPL_H_