To make the switch to async APIs easier, we want to switch bookmark ordering from being tracked as a linked list to being tracked on the folder that they're contained in. See https://wiki.mozilla.org/Places/AsyncAPIsForSync#Predecessor for details.

Should block beta8

On the Firefox side of things we're going to track the ordered list of GUIDs in an annotation on the folder. That way the async Places API won't have to give us this by default but we still avoid a lot of I/O on first sync. I have documented the changes to the bookmark storage format on the wiki: https://wiki.mozilla.org/Labs/Weave/Developer/BrowserObjects

Comment on attachment 495553 [details] [diff] [review] v1 >+ // Reorder children according to the GUID list. Gracefully deal >+ // with missing items, e.g. locally deleted. >+ let delta = 0; >+ for (let idx = 0; idx < children.length; idx++) { >+ let itemid = this.idForGUID(children[idx]); >+ // >+ if (itemid == -1) { empty comment? (have to have at least one nit)

Pushed with nit addressed https://hg.mozilla.org/services/fx-sync/rev/0bd095142655