HasSeenViewportConstrainedAncestor  496 Source/core/rendering/RenderLayer.cpp     if ((flags & HasChangedAncestor) || (flags & HasSeenViewportConstrainedAncestor) || (flags & IsOverflowScroll))
HasSeenViewportConstrainedAncestor  500 Source/core/rendering/RenderLayer.cpp         flags |= HasSeenViewportConstrainedAncestor;