CMS-specific path variables

Since this commit...

https://github.com/civicrm/civicrm-core/commit/f553d1eac3d3bd329fd85d0a2abf7b3acf2a7023

... we have some Wordpress-specific paths being setup on all installations.

Is there a better way of registering these paths only when it's a Wordpress installation?

I would like to add a similar path variable to get to the Drupal 'site' folder for the installation. (If people think that would be a useful addition to core).

A proof of concept is something like:

->register('d7.sitefolder', function () {
  global $civicrm_root;
  $config = \CRM_Core_Config::singleton();
  $siteName = $config->userSystem->parseDrupalSiteNameFromRoot($civicrm_root);
  if (empty($siteName)) {
    $siteName = 'default';
  }
  $route = '[cms.root]/sites/' . $siteName . '/';
  return array(
    'path' => \Civi::paths()->getPath($route),
    'url' => \Civi::paths()->getUrl($route),
  );
})

However, it would be better not to define this on all sites.

(If this would be better in an extension/customisation then it would be great to know how we can add to the default paths?)

Tim Otten, Kevin Cristiano can you offer any advice?