302728 - Review usage of APIs that expect frames to have been reflowed and are clean

Status: NEW

(Core :: Layout: Text and Fonts, defect)

Description

[rbs]

This is a follow-up from bug 252970.

There are APIs such as |GetPointFromOffset| that are expected to be called on
frames for which the NS_FRAME_IS_DIRTY bit is not set--unless the caller knows
what they are doing.

Consider sprinkling them with
NS_ASSERTION(!(mState & NS_FRAME_IS_DIRTY), "internal offsets may be out-of-sync")

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

That assertion isn't really sufficient to guarantee accurate usage, since if an
ancestor is dirty or an ancestor's prior sibling is dirty then the information
could also be out of sync.

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Or even later siblings, in some cases.

So the assertion should probably be that there are no pending reflow requests in
the PresShell, or something like that...