Merge "Add stub for WindowExtensions v2 APIs" into tm-qpr-dev am: 894d5160

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19928849



Change-Id: I9d03bb902a10e2c64e5cddf3116c0185cadd64dc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>