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

device/generic_sensor/public/interfaces/BUILD.gn

+# 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.
+
+import("//mojo/public/tools/bindings/mojom.gni")
+
+mojom("interfaces") {
+  visibility = [ "//device/generic_sensor/public/cpp" ]
+  visibility_blink = [ "//third_party/WebKit/Source/*" ]
+  component_output_prefix = "generic_sensor_public_interfaces"
+  export_class_attribute = "DEVICE_GENERIC_SENSOR_PUBLIC_EXPORT"
+  export_define = "DEVICE_GENERIC_SENSOR_PUBLIC_IMPLEMENTATION=1"
+  export_header =
+      "device/generic_sensor/public/cpp/generic_sensor_public_export.h"
+  sources = [
+    "sensor.mojom",
+    "sensor_provider.mojom",
+  ]
+
+  # TODO(crbug.com/714018): Convert the implementation to use OnceCallback.
+  use_once_callback = false
+}