public function applyBuildListFilter(&$files, $build_list, $component_data) {
    // Case 1: everything was requested: don't filter!
    if (isset($build_list['all'])) {
      return;
    }

    $build_list = array_keys($build_list);

    foreach ($files as $key => $file_info) {
      if (!array_intersect($file_info['build_list_tags'], $build_list)) {
        unset($files[$key]);
      }
    }
  }