function didGetNodePosition(nodePosition)
        {
            if (nodePosition === -1) {
                this.collapse();
                callback(null, null);
            } else {
                this._populateChildren(nodePosition, null, didPopulateChildren.bind(this, nodePosition));
            }
        }
@this {WebInspector.HeapSnapshotConstructorNode}
@param {number} nodePosition