Scheduler/child/TimeSource could be replaced with base/time/DefaultTickClock.

components/scheduler/child/time_source.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 COMPONENTS_SCHEDULER_CHILD_TIME_SOURCE_H_
-#define COMPONENTS_SCHEDULER_CHILD_TIME_SOURCE_H_
-
-#include "base/time/time.h"
-#include "components/scheduler/scheduler_export.h"
-
-namespace scheduler {
-
-class SCHEDULER_EXPORT TimeSource {
- public:
-  TimeSource();
-  virtual ~TimeSource();
-
-  virtual base::TimeTicks Now() const;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(TimeSource);
-};
-
-}  // namespace scheduler
-
-#endif  // COMPONENTS_SCHEDULER_CHILD_TIME_SOURCE_H_