[automerger skipped] Merge "Use abstractions to allow FullscreenUserSwitcher take advantage of SystemUIOverlayWindow." into rvc-dev am: 995e2de8 am: 8d131e35 am: 3db6781e -s ours am: 49c28a9f -s ours
am skip reason: Change-Id I19825da81f8d1b1259a2ba115e0238a9ffa69e37 with SHA-1 84590ea2 is in history

Change-Id: I89c1c3f04c79c12491933c44b1c2a77cb37c13da