function _createLiveDocument(doc, editor, roots) {
        var DocClass = _classForDocument(doc),
            liveDocument;

        if (!DocClass) {
            return null;
        }

        liveDocument = new DocClass(_protocol, _resolveUrl, doc, editor, roots);

        liveDocument.on("errorStatusChanged.livedev", function (event, hasErrors) {
            if (isActive()) {
                _setStatus(hasErrors ? STATUS_SYNC_ERROR : STATUS_ACTIVE);
            }
        });

        return liveDocument;
    }
@private
Create a LiveDocument for a Brackets editor/document to manage communication between the
editor and the browser.
@param {Document} doc
@param {Editor} editor
@param {roots} roots
@return {?LiveDocument} The live document, or null if this type of file doesn't support live editing.