Enable new theme picker preveiw

Also add customize button for customize themes.
Screenshot:
    - Portrait: https://screenshot.googleplex.com/HWmnWEACFdW.png
    - Landscape: https://screenshot.googleplex.com/1NcOQNLoLvE.png

Next: cleanup for res/

Test: Manually
Bug: 146475648
Change-Id: I7624f7404949398dee3782317f0ce0ece8194007
3 files changed