Merge "Split window decor lifecycle to a TransitionObserver" into tm-qpr-dev...

Merge "Split window decor lifecycle to a TransitionObserver" into tm-qpr-dev am: 94cdc7ba am: 163b9c2f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19628835



Change-Id: I4854b6b8d81894b302215ba89a62281e86b21b34
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>