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

device/generic_sensor/linux/platform_sensor_utils_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_PLATFORM_SENSOR_UTILS_LINUX_H_
-#define DEVICE_GENERIC_SENSOR_LINUX_PLATFORM_SENSOR_UTILS_LINUX_H_
-
-#include "base/files/file_path.h"
-#include "base/memory/ptr_util.h"
-#include "device/generic_sensor/generic_sensor_export.h"
-#include "device/generic_sensor/linux/sensor_data_linux.h"
-
-namespace device {
-
-struct SensorDataLinux;
-struct SensorReading;
-
-// Generic reader class that reads sensors data from
-// sensors files located in the base iio folder.
-class DEVICE_GENERIC_SENSOR_EXPORT SensorReader {
- public:
-  ~SensorReader();
-
-  // Creates a new instance of SensorReader if sensor read files
-  // has been found and |sensor_paths_| are set.
-  static std::unique_ptr<SensorReader> Create(const SensorDataLinux& data);
-
-  // Reads sensor values into |*reading| from sensor files
-  // specified in |sensor_paths_|.
-  bool ReadSensorReading(SensorReading* reading);
-
- private:
-  SensorReader(std::vector<base::FilePath> sensor_paths,
-               double scaling_value,
-               const SensorDataLinux::ReaderFunctor& apply_scaling_func);
-
-  // Contains paths to sensor files that are set when
-  // Create() is called.
-  const std::vector<base::FilePath> sensor_paths_;
-
-  // Scaling values that are applied to raw data from sensors.
-  const double scaling_value_;
-
-  // Used to apply scalings and invert signs if needed.
-  const SensorDataLinux::ReaderFunctor apply_scaling_func_;
-
-  DISALLOW_COPY_AND_ASSIGN(SensorReader);
-};
-
-}  // namespace device
-
-#endif  // DEVICE_GENERIC_SENSOR_LINUX_PLATFORM_SENSOR_UTILS_LINUX_H_