frameworks: Smooth background gradient

Credit to UBER for the images

Before: https://app.box.com/s/sarce6zp0zezidc0cdj8

After: https://app.box.com/s/u5ix9u5vb3fjenhzax8b

Change-Id: I3655e9917610348100fa6cb5cede66a63ca82538
Merge "frameworks: Smooth background gradient" into kk4.4