[DO NOT MERGE] Update onBackPressed() function signature am: aaeebdaff9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20155974

Change-Id: I90f72240a22a7660d9162fbc59d5b0a46b265ab6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>