I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[ ] Performance issue
[x] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
[ ] Other... Please describe:

Current behavior

Continuing the discussion in #10981, per @jasonaden's request

Right now, the fix for lazy-loaded auxiliary routes is an internal one, directly tied to routerOutlet. While this is fine for vanilla Angular Apps, Frameworks built on top of Angular, Ionic in this instance, are not able to take advantage of the fix, as our ion-router-outlet is a customized router-outlet.

Expected behavior

The logic used to fix lazy loaded routes internally should be exposed, or configurable for downstream frameworks.

Minimal reproduction of the problem with instructions

Since this is Ionic specific, I've created a sample project

https://github.com/mhartington/lazy-loaded-tabs

What is the motivation / use case for changing the behavior?

The motivation would be for other frameworks using Angular's Router to hook into the EmptyRouterOutlet, but not directly use RouterOutlet.

Environment

Angular version: 6.1.0-beta