Merge "Prototype changes for multitree" am: 55d52209

Original change: https://android-review.googlesource.com/c/platform/build/+/2076562



Change-Id: Id0e9ef26a6a47f6518df77e23b7e9157d0e8c876
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>