[css-overflow] processing model of continue:discard

As noted in the associated issue[1], we need to define how ''continue: discard'' works when the element it is applied to isn't already a fragmentainer.

Rather than defining a new model according to which things may become fragmentainers, I am thinking the I should use the same approach as "continue: fragments" and create a fragment box, the only difference being that you'd only get one, rather than a sequence of fragment boxes.

This implies that ::nth-fragment(1) would work on it, which I think is fine.

Can I go ahead and spec it this way, or does anyone think I should take another approach?

- Florian

[1] http://dev.w3.org/csswg/css-overflow/#issue-36be54be