* Make "Up" and "Overflow" menu icons more visible in AccountProfile
The toolbar in AccountProfile is transparent, so any profile image the user
has chosen is shown under it.
This makes the "Up" and "Overflow" menu icons also have transparent
backgrouns.
Consequently, they can be hard to spot, or possibly invisible, on backgrounds
that are very dark or very light.
Fix this by compositing the icons in a LayerDrawable, with a circular
background identical to the surface colour. This ensures they stand out
against the background image, and blend in when the user scrolls.
* Get and reuse the background drawable
* Apply a smidgen of transparency
70092c8de2