Merge "Resolve 3 inconsistencies in accessibility button API - Unify logic for detecting availability of the accessibility button - Ensure the initial visibility state is propagated to A11yMS - Ensure services only receive availability callbacks for changes" into oc-dev am: 4ab690a50d
am: 5f485cab2b

Change-Id: I9cc746da6edaac51159503d39fab4a2f2a205788