Updating the virtual preloader UX.

> No click feedback when in preloader mode
> No preloader UI when drawn in drag layer
> The preloader consists of a background 9 patch image and a circular progress
is drawn in the content region of the background.
> The preloader is drawn in a slightly larget area than the actual bounds to
make the circular progress more prominent compared to the icon.

issue: 15835307
Change-Id: Ifec3d93ecf1fac994d1128b517da3797247e7ed6