function OptionManager(api) {

	        /**
	         * @private
	         * @type {module:echarts/ExtensionAPI}
	         */
	        this._api = api;

	        /**
	         * @private
	         * @type {Array.<number>}
	         */
	        this._timelineOptions = [];

	        /**
	         * @private
	         * @type {Array.<Object>}
	         */
	        this._mediaList = [];

	        /**
	         * @private
	         * @type {Object}
	         */
	        this._mediaDefault;

	        /**
	         * -1, means default.
	         * empty means no media.
	         * @private
	         * @type {Array.<number>}
	         */
	        this._currentMediaIndices = [];

	        /**
	         * @private
	         * @type {Object}
	         */
	        this._optionBackup;

	        /**
	         * @private
	         * @type {Object}
	         */
	        this._newBaseOption;
	    }
@param {module:echarts/model/Global} ecModel
@return {Object}