chromium/chrome/android/webapk/shell_apk/res_template/values/background_color.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright 2018 The Chromium Authors
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->

<resources>
  <color name="background_color_non_empty">{{{background_color_xml}}}</color>
  <color name="dark_background_color_non_empty">{{{dark_background_color_xml}}}</color>
</resources>