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

components/scheduler/child/scheduler_task_runner_delegate_impl.cc

-// 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.
-
-#include "components/scheduler/child/scheduler_task_runner_delegate_impl.h"
-
-namespace scheduler {
-
-// static
-scoped_refptr<SchedulerTaskRunnerDelegateImpl>
-SchedulerTaskRunnerDelegateImpl::Create(base::MessageLoop* message_loop) {
-  return make_scoped_refptr(new SchedulerTaskRunnerDelegateImpl(message_loop));
-}
-
-SchedulerTaskRunnerDelegateImpl::SchedulerTaskRunnerDelegateImpl(
-    base::MessageLoop* message_loop)
-    : message_loop_(message_loop),
-      message_loop_task_runner_(message_loop->task_runner()) {
-}
-
-SchedulerTaskRunnerDelegateImpl::~SchedulerTaskRunnerDelegateImpl() {
-  RestoreDefaultTaskRunner();
-}
-
-void SchedulerTaskRunnerDelegateImpl::SetDefaultTaskRunner(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
-  message_loop_->SetTaskRunner(task_runner);
-}
-
-void SchedulerTaskRunnerDelegateImpl::RestoreDefaultTaskRunner() {
-  if (base::MessageLoop::current() == message_loop_)
-    message_loop_->SetTaskRunner(message_loop_task_runner_);
-}
-
-bool SchedulerTaskRunnerDelegateImpl::PostDelayedTask(
-    const tracked_objects::Location& from_here,
-    const base::Closure& task,
-    base::TimeDelta delay) {
-  return message_loop_task_runner_->PostDelayedTask(from_here, task, delay);
-}
-
-bool SchedulerTaskRunnerDelegateImpl::PostNonNestableDelayedTask(
-    const tracked_objects::Location& from_here,
-    const base::Closure& task,
-    base::TimeDelta delay) {
-  return message_loop_task_runner_->PostNonNestableDelayedTask(from_here, task,
-                                                               delay);
-}
-
-bool SchedulerTaskRunnerDelegateImpl::RunsTasksOnCurrentThread() const {
-  return message_loop_task_runner_->RunsTasksOnCurrentThread();
-}
-
-bool SchedulerTaskRunnerDelegateImpl::IsNested() const {
-  return message_loop_->IsNested();
-}
-
-void SchedulerTaskRunnerDelegateImpl::AddTaskObserver(
-    base::MessageLoop::TaskObserver* task_observer) {
-  message_loop_->AddTaskObserver(task_observer);
-}
-
-void SchedulerTaskRunnerDelegateImpl::RemoveTaskObserver(
-    base::MessageLoop::TaskObserver* task_observer) {
-  message_loop_->RemoveTaskObserver(task_observer);
-}
-
-}  // namespace scheduler