Make check icon in thumbnail tile vary against system accent color

Mock:
https://docs.google.com/presentation/d/15JadcGi5k1_0znUN_XdFpU7UxeXwxjK3Y7LxvhW5ETM/edit?ts=5eb5f9a8#slide=id.g777aaff414_1_0

Screenshot:
https://screenshot.googleplex.com/D8Oua3hJ5qg.png
https://screenshot.googleplex.com/b4sBUjrQwak.png
https://screenshot.googleplex.com/1NFNw5yGpMR.png

Test: Manually
Fixes: 158429764
Change-Id: Ic20576505bebd61c8cda3e2ccc54973dee62acf8