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

services/device/generic_sensor/platform_sensor_provider.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 SERVICES_DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_PROVIDER_H_
-#define SERVICES_DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_PROVIDER_H_
-
-#include "services/device/generic_sensor/platform_sensor_provider_base.h"
-
-namespace device {
-
-// This a singleton class returning the actual sensor provider
-// implementation for the current platform.
-class PlatformSensorProvider : public PlatformSensorProviderBase {
- public:
-  // Returns the PlatformSensorProvider singleton.
-  // Note: returns 'nullptr' if there is no available implementation for
-  // the current platform.
-  static PlatformSensorProvider* GetInstance();
-
-  // This method allows to set a provider for testing and therefore
-  // skip the default platform provider. This allows testing without
-  // relying on the platform provider.
-  static void SetProviderForTesting(PlatformSensorProvider* provider);
-
- protected:
-  PlatformSensorProvider() = default;
-  ~PlatformSensorProvider() override = default;
-
-  DISALLOW_COPY_AND_ASSIGN(PlatformSensorProvider);
-};
-
-}  // namespace device
-
-#endif  // SERVICES_DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_PROVIDER_H_