Remove unused AllocationBacking am: 8941e34d am: 1675211a am: e4e0ffdf...

Remove unused AllocationBacking am: 8941e34d am: 1675211a am: e4e0ffdf am: f77ada86 am: 4449682a

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2722393



Change-Id: I20281e49644c4c3aaa3406536f9203ad3fe4870c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>