[sensors][win] Implementation of motion sensors for Win platform

device/generic_sensor/generic_sensor_consts.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_GENERIC_SENSOR_CONSTS_H_
 #define DEVICE_GENERIC_SENSOR_GENERIC_SENSOR_CONSTS_H_
 
+#define _USE_MATH_DEFINES
 #include <math.h>
 
 namespace device {
 
 // Required for conversion from G/s^2 to m/s^2
 constexpr double kMeanGravity = 9.80665;
 
 // Required for conversion from deg/s^2 to rad/s^2
 constexpr double kRadiansInDegreesPerSecond = M_PI / 180.0;
 
 // Required for conversion from Gauss to uT.
 constexpr double kMicroteslaInGauss = 100.0;
 
+// Required for conversion from Milligauss to Microtesla.
+constexpr double kMicroteslaInMilligauss = 0.1;
+
 // Default rate for returning value of the ambient light sensor.
 constexpr int kDefaultAmbientLightFrequencyHz = 5;
 
 // Default rate for returning value of the accelerometer sensor.
 constexpr int kDefaultAccelerometerFrequencyHz = 10;
 
 // Default rate for returning value of the gyroscope sensor.
 constexpr int kDefaultGyroscopeFrequencyHz = 10;
 
 // Default rate for returning value of the magnetometer sensor.
 constexpr int kDefaultMagnetometerFrequencyHz = 10;
 
 }  // namespace device
 
 #endif  // DEVICE_GENERIC_SENSOR_GENERIC_SENSOR_CONSTS_H_