code: function _closeRelatedDocument(liveDoc) {
          if (_relatedDocuments[liveDoc.doc.url]) {
              delete _relatedDocuments[liveDoc.doc.url];
          }
  
          if (_server) {
              _server.remove(liveDoc);
          }
  
          _closeDocument(liveDoc);
      }
docs: Removes the given CSS/JSDocument from _relatedDocuments. Signals that the
  given file is no longer associated with the HTML document that is live (e.g.
  if the related file has been deleted on disk).