nsReflowStatus::IsEmpty() assertions are added after DISPLAY_REFLOW in the
beginning of the Reflow().
A few Reflow() implementations have Reset() calls at the end which are left
in place by this patch (with an explanatory comment added to each). These
ending Reset()s are only needed for cases where a non-splittable frame
passes its own nsReflowStatus to a child's reflow method. Just in case the
child leaves a "not fully complete" value in the nsReflowStatus, the
non-splittable parent frame must clear out the nsReflowStatus before
returning, so that its own parent doesn't then try to split it.
MozReview-Commit-ID: 6Jj3jfMAqj4
--HG--
extra : rebase_source : e1fe6a775ad97e16a6d7cc224634ff962ccb0fbf
2e869d8f3d