Reland of [sensors] Ambient light sensor implementation for ChromeOS and Linux.

device/generic_sensor/linux/platform_sensor_utils_linux.h

Index: device/generic_sensor/linux/platform_sensor_utils_linux.h
diff --git a/device/generic_sensor/linux/platform_sensor_utils_linux.h b/device/generic_sensor/linux/platform_sensor_utils_linux.h
new file mode 100644
index 0000000000000000000000000000000000000000..593ba31c4670251b63b0287b1af35aab7931f7a6
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+++ b/device/generic_sensor/linux/platform_sensor_utils_linux.h
@@ -0,0 +1,43 @@
+// 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"
+
+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:
+  explicit SensorReader(std::vector<base::FilePath> sensor_paths);
+
+  // Contains paths to sensor files that are set when
+  // Create() is called.
+  const std::vector<base::FilePath> sensor_paths_;
+
+  DISALLOW_COPY_AND_ASSIGN(SensorReader);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_GENERIC_SENSOR_LINUX_PLATFORM_SENSOR_UTILS_LINUX_H_