Input Outline floating label gap didn't get re-calculated on prefix hide

[glouischandra]

Bug, feature request, or proposal:

Bug: Input Outline floating label gap didn't get re-calculated on prefix hide

What is the expected behavior?

Outline gap is recalculated when prefix gets hidden via *ngIf

What is the current behavior?

Outline gap didn't get recalculated so the experience is pretty broken.

What are the steps to reproduce?

Stackblitz: https://stackblitz.com/edit/angular-nds7ep?file=app%2Finput-overview-example.ts

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Tested with Angular Material 6.4.7

Is there anything else we should know?

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}