[automerger skipped] Merge "Use abstractions to allow FullscreenUserSwitcher take advantage of SystemUIOverlayWindow." into rvc-dev am: 995e2de8 am: 8d131e35 am: 629f6c9f am: eeec1475 am: 1bf53e1c -s ours
am skip reason: Change-Id I19825da81f8d1b1259a2ba115e0238a9ffa69e37 with SHA-1 9a3ef68a is in history

Change-Id: Ia4c8de0c8c69685c7f53b41ec609c0167f3170ec