Add new preview UI for theme picker

- Copied some reviewed part(UI only) from ag/11490179, and added some new code for UI. Will use ag/11490179 to keep going the scale part.
Mock:
https://docs.google.com/presentation/d/15JadcGi5k1_0znUN_XdFpU7UxeXwxjK3Y7LxvhW5ETM/edit?ts=5e69a05c#slide=id.g733fc3779b_39_0

Screenshot:
https://screenshot.googleplex.com/srobRRL70GT.png
https://screenshot.googleplex.com/1DZRPJdYrr8.png
https://screenshot.googleplex.com/G0C08ZgdVsS.png

Test: Manually
Bug: 146475648
Change-Id: Iaa7cba5391a363ca03dfdcf661a41723abf25504