Merge "Add available description for talkback" into sc-dev am: 268234b2 am: e8e93ee5 am: 716bcee1

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

Change-Id: I482f0bef5e3f46c68971d2e0a985c5eb417b36c6