tdLoading uses wrong height if element is hidden when initialized

[freastro]

Bug Report

I tried using tdLoading on an icon within a notification menu to indicate a process that was ongoing. Since the element was hidden when tdLoading was initialized, it used the default height of 100px instead of waiting for the element to become visible. The effect is that the progress spinner is too large for the icon.

Screenshots or link to CodePen/Plunker/JSfiddle

https://covalent-pt5ucb.stackblitz.io

What is the expected behavior?

tdLoading should wait for the element's height to become known or monitor the element's height for changes. Then adjust the progress spinner height as necessary.

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

Ability to use tdLoading on an icon within a menu.

Which version of Angular and Material, and which browser and OS does this issue affect?

Covalent 1.0.0-rc.1 with Angular 5 and Material 5 on macOS Sierra with Google Chrome.