Node access information is indexed in a wrong way

When the node access callback try to index node access info, it assumes that if anonymous users can view the node in the current context, then it's a public node with no special restriction that should always be viewable by anonymous :

      // Check whether all users have access to the node.
      if (!node_access('view', $node, $account)) {
        [...]
      }
      else {
        // Add the generic view grant if we are not using node access or the
        // node is viewable by anonymous users.
        $items[$id]->search_api_access_node = array('node_access__all');
      }

This is not true for some custom node access modules declaring their own realms, for example according to the domain: the node might be publicly viewable on a domain but not on another.

Here's a patch that solves this.