Merge "Use empty data if file in zip has length 0"

    : zip_handle_(handle), zip_entry_(entry), source_(source) {}

std::unique_ptr<IData> ZipFile::OpenAsData() {

  // The file will fail to be mmaped if it is empty

  if (zip_entry_.uncompressed_length == 0) {

    return util::make_unique<EmptyData>();

  }

  if (zip_entry_.method == kCompressStored) {

    int fd = GetFileDescriptor(zip_handle_);