Merge "Update deprecation documentation for onBackPressed" into tm-dev am: 4f774309 am: adb7c463 am: 25f03fe9 am: aa903445

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18090442



Change-Id: Ifa22d5b4b0a2b9d138ab5448e8fd02490374297d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>