[@angular/animations] ViewEncapsulation.ShadowDom breaks Angular Animations

I'm submitting a...


[ ] Regression (a behavior that used to work and stopped working in a new release)
[x] Bug report  
[ ] Performance issue
[ ] 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

As title mentioned, setting ViewEncapsulation.ShadowDom will cause the Animations not being able to run at all. Use-case: I'm building an Angular Element in conjunction with Angular Animations to see if the two play well together.

Expected behavior

Setting ShadowDom Encapsulation strategy should work with Angular Animations.

Minimal reproduction of the problem with instructions

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

Environment


Angular version: 6.1.4


Browser:
- [x] Chrome (desktop) version XX
- [ ] Chrome (Android) version XX
- [ ] Chrome (iOS) version XX
- [ ] Firefox version XX
- [ ] Safari (desktop) version XX
- [ ] Safari (iOS) version XX
- [ ] IE version XX
- [ ] Edge version XX
 
For Tooling issues:
- Node version: 10.x  
- Platform:  Mac

Others: