Introduce a SchedulerHelper in content/child/scheduler

content/renderer/scheduler/nestable_task_runner_for_test.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_RENDERER_SCHEDULER_NESTABLE_TASK_RUNNER_FOR_TEST_H_
-#define CONTENT_RENDERER_SCHEDULER_NESTABLE_TASK_RUNNER_FOR_TEST_H_
-
-#include "content/renderer/scheduler/nestable_single_thread_task_runner.h"
-
-namespace content {
-
-class NestableTaskRunnerForTest : public NestableSingleThreadTaskRunner {
- public:
-  static scoped_refptr<NestableTaskRunnerForTest> Create(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
-
-  void SetNested(bool is_nested);
-
-  // NestableSingleThreadTaskRunner implementation
-  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;
-
- protected:
-  ~NestableTaskRunnerForTest() override;
-
- private:
-  NestableTaskRunnerForTest(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
-
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-  bool is_nested_;
-
-  DISALLOW_COPY_AND_ASSIGN(NestableTaskRunnerForTest);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_SCHEDULER_NESTABLE_TASK_RUNNER_FOR_TEST_H_