Merge "Move transition utility functions into shell.util" into udc-dev am: d3d32373

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21529517



Change-Id: Icd9831497672745c2ddcbcfd82d079bf2b6c828e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>