[sensors] [mac] Implement ambient light sensor for macOS

device/generic_sensor/ambient_light_mac.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 CONTENT_BROWSER_DEVICE_SENSORS_AMBIENT_LIGHT_MAC_H_
-#define CONTENT_BROWSER_DEVICE_SENSORS_AMBIENT_LIGHT_MAC_H_
+#ifndef DEVICE_GENERIC_SENSOR_AMBIENT_LIGHT_MAC_H_
+#define DEVICE_GENERIC_SENSOR_AMBIENT_LIGHT_MAC_H_
 
 #include <IOKit/IOKitLib.h>
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/macros.h"
 
-namespace content {
+namespace device {
 
 // Provides an interface to retrieve ambient light data from MacBooks.
 class AmbientLightSensor {
  public:
   // Create AmbientLightSensor object, return NULL if no valid is sensor found.
   static std::unique_ptr<AmbientLightSensor> Create();
 
+  static double LMUvalueToLux(uint64_t raw_value);
+
   ~AmbientLightSensor();
 
   // Retrieve lux values from Ambient Light Sensor.
   bool ReadSensorValue(uint64_t lux_value[2]);
 
  private:
   AmbientLightSensor();
 
   // Probe the local hardware looking for Ambient Light sensor and
   // initialize an I/O connection to it.
   bool Init();
 
   // IOKit connection to the local sensor.
   io_connect_t io_connection_;
 
   DISALLOW_COPY_AND_ASSIGN(AmbientLightSensor);
 };
 
-}  // namespace content
+}  // namespace device
 
-#endif  // CONTENT_BROWSER_DEVICE_SENSORS_AMBIENT_LIGHT_MAC_H_
+#endif  // DEVICE_GENERIC_SENSOR_AMBIENT_LIGHT_MAC_H_