Merge "Document newly updated NDK/Media constants" into udc-dev am: 2bdb535e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/22080102



Change-Id: I1f03f28e8659971ce2762c13c7898af683f99847
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>