[Sensors] Align sensor reading updates and 'onchange' notification with rAF.

third_party/WebKit/Source/modules/sensor/SensorUpdateNotificationStrategy.h

-// Copyright 2016 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 SensorUpdateNotificationStrategy_h
-#define SensorUpdateNotificationStrategy_h
-
-#include "wtf/Functional.h"
-
-namespace blink {
-
-// This class encapsulates sensor reading update notification logic:
-// the callback is invoked after client calls 'onSensorReadingChanged()'
-// however considering the given sample frequency:
-// guaranteed not to be called more often than expected.
-class SensorUpdateNotificationStrategy {
- public:
-  static std::unique_ptr<SensorUpdateNotificationStrategy> create(
-      double frequency,
-      std::unique_ptr<Function<void()>>);
-
-  virtual void onSensorReadingChanged() = 0;
-  virtual void cancelPendingNotifications() = 0;
-  virtual ~SensorUpdateNotificationStrategy() {}
-};
-
-}  // namespace blink
-
-#endif  // SensorUpdateNotificationStrategy_h