Move blink scheduler implementation into a component

content/child/scheduler/worker_scheduler_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 CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_IMPL_H_
-#define CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_IMPL_H_
-
-#include "content/child/scheduler/worker_scheduler.h"
-#include "content/child/scheduler/scheduler_helper.h"
-
-namespace base {
-namespace trace_event {
-class ConvertableToTraceFormat;
-}
-}
-
-namespace content {
-
-class NestableSingleThreadTaskRunner;
-
-class CONTENT_EXPORT WorkerSchedulerImpl
-    : public WorkerScheduler,
-      public SchedulerHelper::SchedulerHelperDelegate {
- public:
-  explicit WorkerSchedulerImpl(
-      scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner);
-  ~WorkerSchedulerImpl() override;
-
-  // WorkerScheduler implementation:
-  scoped_refptr<base::SingleThreadTaskRunner> DefaultTaskRunner() override;
-  scoped_refptr<SingleThreadIdleTaskRunner> IdleTaskRunner() override;
-  bool CanExceedIdleDeadlineIfRequired() const override;
-  bool ShouldYieldForHighPriorityWork() override;
-  void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer) override;
-  void RemoveTaskObserver(
-      base::MessageLoop::TaskObserver* task_observer) override;
-  void Init() override;
-  void Shutdown() override;
-
-  SchedulerHelper* GetSchedulerHelperForTesting();
-  void SetWorkBatchSizeForTesting(size_t work_batch_size);
-  base::TimeTicks CurrentIdleTaskDeadlineForTesting() const;
-
- protected:
-  // SchedulerHelperDelegate implementation:
-  bool CanEnterLongIdlePeriod(
-      base::TimeTicks now,
-      base::TimeDelta* next_long_idle_period_delay_out) override;
-  void IsNotQuiescent() override {}
-
- private:
-  void MaybeStartLongIdlePeriod();
-
-  SchedulerHelper helper_;
-  bool initialized_;
-
-  DISALLOW_COPY_AND_ASSIGN(WorkerSchedulerImpl);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_IMPL_H_