[FR] Transition on close

[hamonCordova]

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
[ ] Other... Please describe:

Current behavior

When the dialog is closed, it just disappears instantly from the screen

Expected behavior

When the dialog is closed, it could do a "fade-out" transition, for example.
I would like to have a class to create a transition when the dialog is closed.

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

UX improvement

[NetanelBasal]

You're welcome to create a PR