layout method
Resolves the layout of the embedded widget tree.
Implementation
void layout(BoxConstraints constraints, [BuildOwner? owner]) {
if (internalElement == null) {
internalElement = child.createElement();
if (owner != null) {
internalElement!.owner = owner;
}
internalElement!.mount(null);
} else {
internalElement!.update(child);
}
internalElement!.layout(constraints);
}