Merge "Flush BC_FREE_BUFFER and ref ops from non-looper threads." am: 7677da691e

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/541059

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Id38d607606ac8ee2816d2f6722fbd7f117f1da6f