[sensors] [win] Implement ambient light sensor for Windows platform

device/generic_sensor/platform_sensor_win.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 DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_WIN_H_
+#define DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_WIN_H_
+
+#include "base/memory/weak_ptr.h"
+#include "device/generic_sensor/platform_sensor.h"
+#include "device/generic_sensor/platform_sensor_reader_win.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace device {
+
+// Implementation of PlatformSensor interface for Windows platform. Instance
+// of PlatformSensorWin is bound to IPC thread where PlatformSensorProvider is
+// running and communication with Windows platform sensor is done through
+// PlatformSensorReaderWin |sensor_reader_| interface which is bound to sensor
+// thread and communicates with PlatformSensorWin using
+// PlatformSensorReaderWin::Client interface. The error and data change events
+// are forwarded to IPC task runner.
+class PlatformSensorWin final : public PlatformSensor,
+                                public PlatformSensorReaderWin::Client {
+ public:
+  PlatformSensorWin(
+      mojom::SensorType type,
+      mojo::ScopedSharedBufferMapping mapping,
+      PlatformSensorProvider* provider,
+      scoped_refptr<base::SingleThreadTaskRunner> sensor_thread_runner,
+      std::unique_ptr<PlatformSensorReaderWin> sensor_reader);
+
+  PlatformSensorConfiguration GetDefaultConfiguration() override;
+  mojom::ReportingMode GetReportingMode() override;
+
+  // PlatformSensorReaderWin::Client interface implementation.
+  void OnReadingUpdated(const SensorReading& reading) override;
+  void OnSensorError() override;
+
+ protected:
+  ~PlatformSensorWin() override;
+
+  // PlatformSensor interface implementation.
+  bool StartSensor(const PlatformSensorConfiguration& configuration) override;
+  void StopSensor() override;
+  bool CheckSensorConfiguration(
+      const PlatformSensorConfiguration& configuration) override;
+
+ private:
+  scoped_refptr<base::SingleThreadTaskRunner> sensor_thread_runner_;
+  PlatformSensorReaderWin* const sensor_reader_;
+  base::WeakPtrFactory<PlatformSensorWin> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PlatformSensorWin);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_WIN_H_