Warning: file_get_contents(): Filename cannot be empty in _locale_parse_js_file() includes/locale.inc)

Warning: file_get_contents(): Filename cannot be empty in _locale_parse_js_file() includes/locale.inc)

backtrace:

file_get_contents('') locale.inc:1502
_locale_parse_js_file('https://maps.googleapis.com/maps/api/js?sensor=true') locale.module:917
locale_js_alter(Array, NULL, NULL, NULL) module.inc:1109
drupal_alter('js', Array) common.inc:4271
drupal_get_js('footer') theme.inc:2631
template_process_html(Array, 'html') theme.inc:1122
theme('html', Array) common.inc:5930
drupal_render(Array) common.inc:5777

Looking at the code I am not sure what is done with external js files like this.

the locale.inc file is:

function _locale_parse_js_file($filepath) {
  global $language;

  // The file path might contain a query string, so make sure we only use the
  // actual file.
  $parsed_url = drupal_parse_url($filepath);
  $filepath = drupal_realpath($parsed_url['path']);
  // Load the JavaScript file.

  $file = file_get_contents($filepath);

At https://api.drupal.org/api/drupal/includes%21common.inc/function/drupal_... api.drupal.org on drupal.parse.url states:
This function should only be used for URLs that have been generated by the system, such as via url(). It should not be used for URLs that come from external sources, or URLs that link to external resources.