The index of a fragment in a flattened vector of DOM elements.
Flows for inline layout.
Represents a list of inline fragments, including element ranges.
Ascent and space needed above and below the baseline for a fragment. See CSS 2.1 § 10.8.1.
Lines are represented as offsets into the child list, rather than
as an object that “owns” fragments. Choosing a different set of line
breaks requires a new list of offsets, and possibly some splitting and
merging of TextFragments.
Arranges fragments into lines, splitting them up as necessary.