mình sửa  **file.module** đường dẫn theo đường dẫn **/modules/file**
/**
 * Returns HTML for an image with an appropriate icon for the given file.
 *
 * @param $variables
 *   An associative array containing:
 *   - file: A file object for which to make an icon.
 *   - icon_directory: (optional) A path to a directory of icons to be used for
 *     files. Defaults to the value of the "file_icon_directory" variable.
 *   - alt: (optional) The alternative text to represent the icon in text-based
 *     browsers. Defaults to an empty string.
 *
 * @ingroup themeable
 */
function theme_file_icon($variables) {
  $file = $variables['file'];
  $alt = $variables['alt'];
  $icon_directory = $variables['icon_directory'];

  $mime = check_plain($file->filemime);
  $icon_url = file_icon_url($file, $icon_directory);
  $url = file_create_url($file->uri); /*Thêm đường dẫn file */
  return '<a href='.$url.'><img class="file-icon" alt="' . check_plain($alt) . '" title="' . $mime . '" src="' . $icon_url . '" /></a>'; /* Thêm link vào icon */
}

Sau đó dùng css ẩn cái tên file là ok. 
Cảm ơn **Mahyar Farshi** đã chia sẻ.