Revert of Move //device/generic_sensor to be part of the internal implementation of the Device Service.

device/generic_sensor/platform_sensor_provider_mac.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_PROVIDER_MAC_H_
+#define DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_PROVIDER_MAC_H_
+
+#include "device/generic_sensor/platform_sensor_provider.h"
+
+namespace device {
+
+class PlatformSensorProviderMac : public PlatformSensorProvider {
+ public:
+  PlatformSensorProviderMac();
+  ~PlatformSensorProviderMac() override;
+
+  static PlatformSensorProviderMac* GetInstance();
+
+ protected:
+  void CreateSensorInternal(mojom::SensorType type,
+                            mojo::ScopedSharedBufferMapping mapping,
+                            const CreateSensorCallback& callback) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PlatformSensorProviderMac);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_PROVIDER_MAC_H_