Merge "Add available description for talkback" into sc-dev am: 268234b2 am: 6c5447ae am: fe5cade7

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15235315

Change-Id: I4e950d1cc5b832ad0a12f6a3dfb760c2d7785005