Revert of Add a WorkerScheduler and a WebThreadImplForWorker

content/child/scheduler/null_worker_scheduler.cc

-// Copyright 2014 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 "content/child/scheduler/null_worker_scheduler.h"
-
-#include "base/bind.h"
-#include "base/message_loop/message_loop_proxy.h"
-#include "content/child/scheduler/null_idle_task_runner.h"
-
-namespace content {
-
-NullWorkerScheduler::NullWorkerScheduler()
-    : task_runner_(base::MessageLoopProxy::current()),
-      idle_task_runner_(new NullIdleTaskRunner()) {
-}
-
-NullWorkerScheduler::~NullWorkerScheduler() {
-}
-
-scoped_refptr<base::SingleThreadTaskRunner>
-NullWorkerScheduler::DefaultTaskRunner() {
-  return task_runner_;
-}
-
-scoped_refptr<SingleThreadIdleTaskRunner>
-NullWorkerScheduler::IdleTaskRunner() {
-  return idle_task_runner_;
-}
-
-void NullWorkerScheduler::AddTaskObserver(
-    base::MessageLoop::TaskObserver* task_observer) {
-  base::MessageLoop::current()->AddTaskObserver(task_observer);
-}
-
-void NullWorkerScheduler::RemoveTaskObserver(
-    base::MessageLoop::TaskObserver* task_observer) {
-  base::MessageLoop::current()->RemoveTaskObserver(task_observer);
-}
-
-bool NullWorkerScheduler::CanExceedIdleDeadlineIfRequired() const {
-  return false;
-}
-
-void NullWorkerScheduler::Init() {
-}
-
-void NullWorkerScheduler::Shutdown() {
-}
-
-}  // namespace content