[Sensors] Improvements in fetching reading for sensors with continuous reporting mode

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

Index: third_party/WebKit/Source/modules/sensor/SensorUpdateNotificationStrategy.h
diff --git a/third_party/WebKit/Source/modules/sensor/SensorUpdateNotificationStrategy.h b/third_party/WebKit/Source/modules/sensor/SensorUpdateNotificationStrategy.h
new file mode 100644
index 0000000000000000000000000000000000000000..720e9a124e2d6b2ada6b0e99d0137c5b6dd134e3
--- /dev/null
+++ b/third_party/WebKit/Source/modules/sensor/SensorUpdateNotificationStrategy.h
@@ -0,0 +1,29 @@
+// 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