1951751 - [css-grid] Use the correct items for calculating the grid baseline

Status: NEW

(Core :: Layout: Grid, defect)

Description

[Tiaan Louw]

Find the first (last) row of the grid container containing at least one grid item.

If any of the grid items intersecting this row participate in baseline alignment in that row, the grid container’s baseline set is generated from the shared alignment baseline of those grid items.

Otherwise, the grid container’s first (last) baseline set is generated from the alignment baseline of the first (last) grid item in row-major grid order (according to the writing mode of the grid container). If the grid item has no alignment baseline in the grid’s inline axis, then one is first synthesized from its border edges.

We're failing the first part here: https://searchfox.org/mozilla-central/rev/a2abcf7ff6b7ae0c2d8a04b9a35679f8c84634e7/layout/generic/nsGridContainerFrame.cpp#6167

We are doing the 2nd part, but failing the 3rd part possibly here: https://searchfox.org/mozilla-central/rev/a2abcf7ff6b7ae0c2d8a04b9a35679f8c84634e7/layout/generic/nsGridContainerFrame.cpp#9975