[Sensors] Implementation of the Generic Sensor API

third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.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 SensorPollingStrategy_h
+#define SensorPollingStrategy_h
+
+#include "device/generic_sensor/public/interfaces/sensor_provider.mojom-blink.h"
+#include "platform/heap/Handle.h"
+#include "wtf/Functional.h"
+
+namespace blink {
+
+// This class provides different polling behaviour depending on
+// the given 'ReportingMode':
+// - for 'CONTINUOUS' mode the polling function is invoked periodically
+//   with the given frequency (on timer event).
+// - for 'ONCHANGE' mode the polling function is invoked only after client
+//   calls 'onSensorReadingChanged()' however considering the given frequency:
+//   guaranteed not to be called more often than expected.
+class SensorPollingStrategy {
+public:
+    static std::unique_ptr<SensorPollingStrategy> create(double frequency, std::unique_ptr<Function<void()>> pollFunc, device::mojom::blink::ReportingMode);
+
+    virtual void onSensorReadingChanged() {}
+    virtual void startPolling() = 0;
+    virtual void stopPolling() = 0;
+
+    virtual ~SensorPollingStrategy() {}
+};
+
+} // namespace blink
+
+#endif // SensorPollingStrategy_h