76767 - refactor nsBlockFrame

Status: NEW

(Core :: Layout: Block and Inline, defect, P5)

Description

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

I think at some point nsBlockFrame needs a major cleanup.  Here are some ideas I
think might work (although I haven't thought them through well enough yet to
really have a good idea how they might work):

 * It would be good to store vertical margins in separate structures, say,
nsBlockVerticalMargin (or maybe something a little shorter), since a single
vertical margin can be associated with an arbitrary number of blocks.

 * It might (I've thought about this even less) be nice to split nsBlockFrame
into two classes:  nsBlockFrame and nsBlockInnerFrame -- the outer one would
contain only other block frames, tables and nsBlockInnerFrames, and the inner
one would serve as a container for lines.  The current way the mLines array
stores both block and inline children has always seemed weird to me and I think
the code might end up being simpler if we distinguished between them.  Or
something like that...

I'm not sure if other people had been thinking about similar things, but I
wanted to jot these ideas down in a bug before I forgot them...