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: I6e84f1c4b10d45de40f89cdddd4570f4c0e2a3c6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>