calculateSize

Use this function to calculate the size of this component. DO NOT include children in this calculation!

This function is only called if no size is supplied to this component at initialization. A return value of null indicates this component is not able to infer its own size, as it is for example, a Block with no reference. A component such as Text on the other hand, is able to infer its own size.

This function is only ever called if sizeValid is false.