[automerger skipped] Add RootTargetPreparer for explicitly specifying the root...

[automerger skipped] Add RootTargetPreparer for explicitly specifying the root dependency am: 58077070 am: 61dfa97c -s ours am: 03b40df6 -s ours am: 271c234d -s ours

am skip reason: Merged-In I9b34a85025a6aa4f138483202fd11db0cbb8b04b with SHA-1 3c4f5273 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/26928402



Change-Id: I2f8f28526e8431b14519fede3300ed176ebd19f3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>