Add elevation effect for buttom action bar

Before:
https://screenshot.googleplex.com/6AKO6cTzebj.png
https://screenshot.googleplex.com/c9mkDWSNiu7.png
After:
https://screenshot.googleplex.com/rfBrN5hhApO.png
https://screenshot.googleplex.com/Sq2Z2WMhFHV.png
Video:
https://drive.google.com/file/d/1ieZqCqWz6OnLrxKAbC2It6BCakq_-34F/view?usp=sharing

Test: Manually
Bug: 155353471
Change-Id: I6a7ad9d00e5b82acfbb4f601a8b550cec9c274de
2 files changed