Merge "stagefright: notify async release complete" into rvc-dev am: 3244d0db...

Merge "stagefright: notify async release complete" into rvc-dev am: 3244d0db am: cb2a9094 am: 0d114fc6 am: 385bbff0

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/11795217

Change-Id: I3ac9934f452670ee443d25480a5e35edd66eb3b6