Merge "Add RootTargetPreparer for explicitly specifying the root dependency" into main am: 5613fb78ee am: ea9718838f

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2963562

Change-Id: I2eb6a12db58dfb71ea4ecb3791c27f596b8f0493
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>