Merge "Support building crate variants." am: eb91e5586a

Original change: https://android-review.googlesource.com/c/platform/development/+/2368768

Change-Id: I6d566bd8fd9392bfa68bc5e852332f80df023bea
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>