Merge "Empty attribute values in styles should be strings"

    return std::move(string);

  }

  // If the text is empty, and the value is not allowed to be a string, encode it as a @null.

  if (util::TrimWhitespace(raw_value).empty()) {

    return ResourceUtils::MakeNull();

  }

  if (allow_raw_value) {

    // We can't parse this so return a RawString if we are allowed.

    return util::make_unique<RawString>(

        table_->string_pool.MakeRef(util::TrimWhitespace(raw_value),

                                    StringPool::Context(config_)));

  } else if (util::TrimWhitespace(raw_value).empty()) {

    // If the text is empty, and the value is not allowed to be a string, encode it as a @null.

    return ResourceUtils::MakeNull();

  }

  return {};

}