Clarify the order that lines/fragments/glyphs are put in lists: visual or source order?

[travisleithead]

From CG meeting on 8/18

Clarify the order that things are put into the lists (especially at the fragment level): visual order or source order? Will matter for bidi formatted runs.

[nhelfman]

My vote for visual order - this is the main advantage of using the API to draw text in order without worrying about bidi run resolution.