function setFolds(path, folds) {
        var context = getViewStateContext();
        var allFolds = PreferencesManager.getViewState(FOLDS_PREF_KEY, context);
        allFolds[path] = simplify(folds);
        PreferencesManager.setViewState(FOLDS_PREF_KEY, allFolds, context);
    }
Saves the line folds for the specified path
@param {!string} path the path to the document
@param {Object} folds the fold ranges to save for the current document