[sensors] [mac] Implement ambient light sensor for macOS

device/generic_sensor/platform_sensor_ambient_light_mac.h

Index: device/generic_sensor/platform_sensor_ambient_light_mac.h
diff --git a/device/generic_sensor/platform_sensor_ambient_light_mac.h b/device/generic_sensor/platform_sensor_ambient_light_mac.h
new file mode 100644
index 0000000000000000000000000000000000000000..eebf81e2a400176b2c265b73a7a8984838d1d3b8
--- /dev/null
+++ b/device/generic_sensor/platform_sensor_ambient_light_mac.h
@@ -0,0 +1,54 @@
+// 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_PLATFORM_SENSOR_AMBIENT_LIGHT_SENSOR_MAC_H_
+#define DEVICE_GENERIC_PLATFORM_SENSOR_AMBIENT_LIGHT_SENSOR_MAC_H_
+
+#include <IOKit/IOKitLib.h>
+
+#include "base/mac/scoped_ioobject.h"
+#include "device/generic_sensor/platform_sensor.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace device {
+
+class PlatformSensorAmbientLightMac : public PlatformSensor {
+ public:
+  PlatformSensorAmbientLightMac(
+      mojom::SensorType type,
+      mojo::ScopedSharedBufferMapping mapping,
+      uint64_t buffer_size,
+      PlatformSensorProvider* provider,
+      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);

[Robert Sesek, 2016/10/04 15:28:18]

There's no reason to explicitly name this for the ui_task_runner. This could be
used to receive callbacks on any thread. (Same with the member variable name).

+
+  mojom::ReportingMode GetReportingMode() override;
+  bool StartSensor(const PlatformSensorConfiguration& configuration) override;
+  void StopSensor() override;
+
+ protected:
+  ~PlatformSensorAmbientLightMac() override;
+  bool CheckSensorConfiguration(
+      const PlatformSensorConfiguration& configuration) override;
+  PlatformSensorConfiguration GetDefaultConfiguration() override;
+  void UpdateReading(uint64_t lux_values[2]);
+
+ private:
+  static void IOServiceCallback(void* context,
+                                io_service_t service,
+                                natural_t message_type,
+                                void*);
+  base::mac::ScopedIOObject<io_service_t> light_sensor_service_;

[Reilly Grant (use Gerrit), 2016/10/04 07:11:27]

nit: space between methods and fields

+  IONotificationPortRef light_sensor_port_;

[Reilly Grant (use Gerrit), 2016/10/04 07:11:27]

Initialize this to nullptr.

+  io_object_t light_sensor_object_;
+  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
+  double current_lux_;
+  DISALLOW_COPY_AND_ASSIGN(PlatformSensorAmbientLightMac);

[Reilly Grant (use Gerrit), 2016/10/04 07:11:27]

nit: space between fields and this macro

+};
+
+}  // namespace device
+
+#endif  // DEVICE_GENERIC_PLATFORM_SENSOR_AMBIENT_LIGHT_SENSOR_MAC_H_