material next changes for button color

Bug: 191423382
Test: Manual

Screenshot:
Android S:
https://screenshot.googleplex.com/8Fqj3JLunigDede.png
https://screenshot.googleplex.com/47XCKswqC8vC7Kg.png

Android R:
https://screenshot.googleplex.com/PmuFT6jPbFipf28.png
https://screenshot.googleplex.com/7gkUJUe87T2Sn7g.png

Change-Id: Icf23f7a977d077ec43fc2a38fad49923ce5f962f