[CSSOM] does CaretPosition need a "before/after" hint?

Gecko's internal equivalent of CaretPosition has a flag that we use to
disambiguate "the caret is after character N-1 of the text node" and "the
character is before character N of the text node". This matters because in
bidi situations the screen positions of those caret locations can be
different. For example, consider the text node "Latin HEBREW" rendered as
Latin WERBEH
If the caret is after the space, then it should be displayed in the middle
of the line. If the caret is before the H, it should be displayed at the end
of the line.

Does the CSSOM CaretPosition need to expose something similar?

Rob
-- 
"Now the Bereans were of more noble character than the Thessalonians, for
they received the message with great eagerness and examined the Scriptures
every day to see if what Paul said was true." [Acts 17:11]