Merge "Introduce setSplashscreenStyle to specify splash screen style." into sc-dev am: 6b0741b3 am: b0682668 am: 1527f782

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/14609925

Change-Id: Id4261ef9e0bd6b78161ac9bfc38ceda6a6bff024