function _addWelcomeProjectPath(path, currentProjects) {
        var pathNoSlash = FileUtils.stripTrailingSlash(path);  // "welcomeProjects" pref has standardized on no trailing "/"

        var newProjects;

        if (currentProjects) {
            newProjects = _.clone(currentProjects);
        } else {
            newProjects = [];
        }

        if (newProjects.indexOf(pathNoSlash) === -1) {
            newProjects.push(pathNoSlash);
        }
        return newProjects;
    }
@private

Adds the path to the list of welcome projects we've ever seen, if not on the list already.

@param {string} path Path to possibly add
@param {Array.<string>=} currentProjects Array of current welcome projects
@return {Array.<string>} New array of welcome projects with the additional project added