colCustomContextFromGates(col, outerRowOffset) {
        if (col < 0 || col >= this.columns.length) {
            return new Map();
        }
        let key = "" + outerRowOffset;
        let result = this._cachedColumnContexts.get(key);
        if (result === undefined) {
            result = this._uncached_customContextFromGates(outerRowOffset);
            this._cachedColumnContexts.set(key, result);
        }
        return result[col];
    }
@param {!int} col
@param {!int} outerRowOffset
@returns {!Map.<!string, *>}