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

[automerger skipped] Add RootTargetPreparer for explicitly specifying the root dependency am: fb283ce5 am: 8b1efdc4 am: cfbb9d94 am: 2ae19061 am: 9b84bba1 am: 82d28994 am: 169556ae -s ours

am skip reason: Merged-In I4b86fd5ee31f746942a2bf073a29cb2180a39f27 with SHA-1 76aa9d6a is already in history

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



Change-Id: I6e7033603b920a69125bc68e3be7777599df9a33
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>