layer.contentFrame()

The calculated frame for the total size of all the children combined.
译：计算框架各层的总大小组合。

layerA = new Layer
layerB = new Layer
    parent: layerA
    x: 0
    width: 100

layerC = new Layer
    parent: layerA
    x: 100
    width: 300

print layerA.contentFrame()
# Output: { x: 0, y: 0, width: 400, height: 100 }