Merge "Apply root task for launch activity animation." into udc-dev am:...

Merge "Apply root task for launch activity animation." into udc-dev am: 181bcdba am: e2cdba05 am: 3290f016

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23109637



Change-Id: I671b4b04a69136daa7c41818696ccb50339f4ee4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>