Host rectangle takes width of inner centered content

import QtQuick 1.0


Rectangle {
    id: outerRect
    width: childrenRect.width;
    height: childrenRect.height
    color: "lightblue"
    Rectangle {
        width: childrenRect.width
        height: childrenRect.height
        Row {
            id: innerChild
            spacing: 10
            Rectangle {
                width: 100
                height: 100
                color: "red"
            }
            Rectangle {
                width: 100
                height: 100
                color: "green"
            }
            Rectangle {
                width: 100
                height: 100
                color: "blue"
            }
        }
    }
}