[sensors] Introduce Generic Sensor API interfaces

device/generic_sensor/platform_sensor_configuration.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_PLATFORM_SENSOR_CONFIGURATION_H_
+#define DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_CONFIGURATION_H_
+
+#include "base/logging.h"
+#include "device/generic_sensor/sensor_export.h"
+
+namespace device {
+
+class DEVICE_SENSOR_EXPORT PlatformSensorConfiguration {
+ public:
+  PlatformSensorConfiguration();
+  explicit PlatformSensorConfiguration(double frequency);
+  ~PlatformSensorConfiguration();
+
+  bool operator==(const PlatformSensorConfiguration& other) const;
+
+  void set_frequency(double frequency) {
+    DCHECK(frequency_ <= kMaxAllowedFrequency && frequency_ > 0.0);
+    frequency_ = frequency;
+  }
+
+  double frequency() const { return frequency_; }
+
+  static constexpr double kMaxAllowedFrequency = 60.0;
+
+ private:
+  double frequency_ = 1.0;  // 1 Hz by default.
+};
+
+}  // namespace device
+
+#endif  // DEVICE_SENSORS_PLATFORM_SENSOR_CONFIGURATION_H_