[automerger skipped] Add RootTargetPreparer for explicitly specifying the root dependency am: fb283ce556 am: 8b1efdc4e2 am: cfbb9d947f am: 2ae190613a am: 18c1440c7c am: 9ac3050641 am: a92592d650 am: 083aefd92b am: cd61d98ff2 -s ours

am skip reason: Merged-In I4b86fd5ee31f746942a2bf073a29cb2180a39f27 with SHA-1 76aa9d6ab1 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/26681387

Change-Id: I5248c477d6da86fcc1120b813fad318d052a4a0d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>