Merge "Preload WindowManager Extensions to improve startup performance" into udc-dev am: 1349f576 am: ef25fad5

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21502526



Change-Id: I5037a3017f405efe347845295bf6f1967338a69d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>