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

device/sensors/public/cpp/BUILD.gn

Index: device/sensors/public/cpp/BUILD.gn
diff --git a/ash/public/cpp/BUILD.gn b/device/sensors/public/cpp/BUILD.gn
similarity index 71%
copy from ash/public/cpp/BUILD.gn
copy to device/sensors/public/cpp/BUILD.gn
index ea64e0fbe9c48e6a9f8851c76a72ade685b08f6a..a47cf31a73144c82d37770281daccf9dd08abb45 100644
--- a/ash/public/cpp/BUILD.gn
+++ b/device/sensors/public/cpp/BUILD.gn
@@ -2,9 +2,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# C++ headers and sources that can be used outside ash.
 source_set("cpp") {
   sources = [
-    "shelf_types.h",
+    "device_sensors_consts.h",
+    "device_util_mac.cc",
+    "device_util_mac.h",
   ]
 }