function _getNoRulesMsg() {
            var result = new $.Deferred();
            _getCSSFilesInProject().done(function (fileInfos) {
                result.resolve(fileInfos.length ? Strings.CSS_QUICK_EDIT_NO_MATCHES : Strings.CSS_QUICK_EDIT_NO_STYLESHEETS);
            });
            return result;
        }
@private
Checks to see if there are any stylesheets in the project, and returns the appropriate
"no rules"/"no stylesheets" message accordingly.
@return {$.Promise} a promise that is resolved with the message to show. Never rejected.