$mdDialog doesn't work correctly when have scrollbar

[marcomafessolli]

Actual behavior:

• When the browser/container have a scrollbar $mdDialog doesn't work properly, creating some kind of "mask" at the bottom of the browser.

CodePen

• http://codepen.io/marcomafessolli/pen/pbvyLW

Angular Versions:

• Angular Material Version: Master

Additional Information:

• Browser Type: Tested on Chrome and Safari
• OS: MacOS

[crisbeto]

Seems like I introduced this with #8349, I'll look into it.