Adding a Child View Controller to Your Content

https://developer.apple.com/library/content/featuredarticles/ViewControllerPGforiPhoneOS/ImplementingaContainerViewController.html#//apple_ref/doc/uid/TP40007457-CH11-SW13

1. - (void) displayContentController: (UIViewController*) content {
2. [self addChildViewController:content];
3. content.view.frame = [self frameForContentController];
4. [self.view addSubview:self.currentClientView];
5. [content didMoveToParentViewController:self];
6. }