function minifyFontObject(ttfObject, subset, plugin) {

    // check null
    if (subset.length === 0) {
        return ttfObject;
    }

    // new TTF Object
    var ttf = new fonteditorCore.TTF(ttfObject);

    // get target glyfs then set
    ttf.setGlyf(getSubsetGlyfs(ttf, subset));

    // use plugin
    if (_.isFunction(plugin)) {
        plugin(ttf);
    }

    return ttf.get();
}
minifyFontObject

@param  {Object} ttfObject    ttfObject
@param  {Array} subset         subset
@param  {Function=} plugin       use plugin
@return {Object}              ttfObject