Move blink scheduler implementation into a component

content/child/scheduler/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 CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_H_
-#define CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_H_
-
-#include "base/message_loop/message_loop.h"
-#include "content/child/scheduler/child_scheduler.h"
-#include "content/child/scheduler/single_thread_idle_task_runner.h"
-#include "content/common/content_export.h"
-
-namespace base {
-class MessageLoop;
-}
-
-namespace content {
-
-class CONTENT_EXPORT WorkerScheduler : public ChildScheduler {
- public:
-  ~WorkerScheduler() override;
-  static scoped_ptr<WorkerScheduler> Create(base::MessageLoop* message_loop);
-
-  // Must be called before the scheduler can be used. Does any post construction
-  // initialization needed such as initializing idle period detection.
-  virtual void Init() = 0;
-
- protected:
-  WorkerScheduler();
-  DISALLOW_COPY_AND_ASSIGN(WorkerScheduler);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_H_