ASManagesChildVisibilityDepth Protocol Reference
A protocol which should be implemented by container view controllers to allow proper propagation of visibility depth
Container view controllers should adopt this protocol to indicate that they will manage their child’s visibilityDepth. For example, ASNavigationController adopts this protocol and manages its childrens visibility depth.
If you adopt this protocol, you must also emit visibilityDepthDidChange messages to child view controllers.
- (NSInteger)visibilityDepthOfChildViewController:(UIViewController *)childViewController
Expected to return the visibility depth of the child view controller.