[sensors][mac] Make sure to update the sensor value when initializing the sensor.

device/generic_sensor/platform_sensor_ambient_light_mac.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_PLATFORM_SENSOR_AMBIENT_LIGHT_SENSOR_MAC_H_
 #define DEVICE_GENERIC_PLATFORM_SENSOR_AMBIENT_LIGHT_SENSOR_MAC_H_
 
 #include <IOKit/IOKitLib.h>
 
 #include "base/mac/scoped_ionotificationportref.h"
@@ skipping 22 matching lines @@
   mojom::ReportingMode GetReportingMode() override;
   // Can only be called once, the first time or after a StopSensor call.
   bool StartSensor(const PlatformSensorConfiguration& configuration) override;
   void StopSensor() override;
 
  protected:
   ~PlatformSensorAmbientLightMac() override;
   bool CheckSensorConfiguration(
       const PlatformSensorConfiguration& configuration) override;
   PlatformSensorConfiguration GetDefaultConfiguration() override;
-  void UpdateReading(uint64_t lux_values[2]);
 
  private:
+  bool ReadAndUpdate();
   static void IOServiceCallback(void* context,
                                 io_service_t service,
                                 natural_t message_type,
                                 void* message_argument);
 
   // IOService representing the LMU sensor.
   base::mac::ScopedIOObject<io_service_t> light_sensor_service_;
   // Port used to get the notifications from the sensor.
   base::mac::ScopedIONotificationPortRef light_sensor_port_;
   // IO Object used to query the value of the sensor.
   base::mac::ScopedIOObject<io_object_t> light_sensor_object_;
   // IO Notifications created by IOServiceAddInterestNotification.
   base::mac::ScopedIOObject<io_object_t> light_sensor_notification_;
   double current_lux_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformSensorAmbientLightMac);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_GENERIC_PLATFORM_SENSOR_AMBIENT_LIGHT_SENSOR_MAC_H_