[css-flexbox] intrinsic sizing

Hi there,

got a question about http://dev.w3.org/csswg/css-flexbox/#intrinsic-sizes

It says "For each flex item, subtract its flex base size from its
max-content contribution size"

However, doesn't calculating the flex base size require laying out the
item? I didn't think that calculating intrinsic widths should require
layout?

My second question is:
"Place all flex items into lines of infinite length."

If we place them on lines of infinite length, doesn't that mean we
have just a single line?

thanks,
-christian