[automerger skipped] Merge "Use abstractions to allow FullscreenUserSwitcher take advantage of SystemUIOverlayWindow." into rvc-dev am: 995e2de8 am: 8d131e35 am: 3db6781e -s ours
am skip reason: Change-Id I19825da81f8d1b1259a2ba115e0238a9ffa69e37 with SHA-1 84590ea2 is in history

Change-Id: I9eb14d8ca3bfcf95eafdfb3f0eb45b6d9c04136d