set small(x)
    {
        this._small = x;
        if (this.listItemElement)
            this.listItemElement.classList.toggle("small", this._small);
    }
@constructor
@extends {TreeElement}
@param {string} className
@param {string} title
@param {string=} subtitle
@param {?Object=} representedObject
@param {boolean=} hasChildren