[sensors](CrOS/Linux) Implement Sensor device manager for sensors

device/generic_sensor/linux/sensor_data_linux.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_LINUX_SENSOR_DATA_LINUX_H_
 #define DEVICE_GENERIC_SENSOR_LINUX_SENSOR_DATA_LINUX_H_
 
 #include "device/generic_sensor/generic_sensor_export.h"
 #include "device/generic_sensor/public/interfaces/sensor.mojom.h"
 
 namespace device {
 
+class PlatformSensorConfiguration;
 struct SensorReading;
 
 // This structure represents a context that is used to
 // create a type specific SensorReader and a concrete
 // sensor that uses the SensorReader to read sensor
 // data from files specified in the |sensor_file_names|.
 struct DEVICE_GENERIC_SENSOR_EXPORT SensorDataLinux {
-  using ReaderFunctor =
-      base::Callback<void(double scaling, SensorReading& reading)>;
+  using ReaderFunctor = base::Callback<
+      void(double scaling, double offset, SensorReading& reading)>;
 
   SensorDataLinux();
   ~SensorDataLinux();
   SensorDataLinux(const SensorDataLinux& other);
   // Provides a base path to all sensors.
   const base::FilePath::CharType* base_path_sensor_linux;
   // Provides an array of sensor file names to be searched for.
   // Different sensors might have up to 3 different file name arrays.
   // One file must be found from each array.
   std::vector<std::vector<std::string>> sensor_file_names;
   // Scaling file to be found.
   std::string sensor_scale_name;
+  // Frequency file to be found.
+  std::string sensor_frequency_file_name;
+  // Offset file to be found.
+  std::string sensor_offset_file_name;
   // Used to apply scalings to raw sensor data.
   ReaderFunctor apply_scaling_func;
-  // Reporting mode of a sensor.
-  mojom::ReportingMode reporting_mode;
+  // Sensor type
+  mojom::SensorType type;
   // Default configuration of a sensor.
   PlatformSensorConfiguration default_configuration;
 };
 
 // Initializes a sensor type specific data.
-bool InitSensorData(mojom::SensorType type, SensorDataLinux* data);
+bool DEVICE_GENERIC_SENSOR_EXPORT InitSensorData(mojom::SensorType type,
+                                                 SensorDataLinux* data);
 
 }  // namespace device
 
 #endif  // DEVICE_GENERIC_SENSOR_LINUX_SENSOR_DATA_LINUX_H_