Part 1: Remove current table item, as it's never set.
Part 2: Get rid of generic table painting code, and handle each class separately.
Part 4: Hoist outline skipping into col(group) frame code.
Part 5: Skip box-shadow for table column and column groups.
Part 6: Store column and column group backgrounds separately, and then append them before the rest of the table contents.
Part 7: Pass rects in display list coordinates to AppendBackgroundItemsToTop.
Part 8: Create column and column group background display items as part of the cell's BuildDisplayList.
Part 9: Used cached values instead of calling nsDisplayListBuilder::ToReferenceFrame when possible, since it can be expensive when the requested frame isn't the builder's current frame.
Part 10: Make sure we build display items for table parts where only the normal position is visible, since we may need to create background items for ancestors at that position.
Part 11: Create an AutoBuildingDisplayList when we create background items for table columns and column groups, so that we initialize the invalidation state correctly.
List of relevant patches applied:
1398537 part 2 - [css-multicol] Implement percentages for 'column-gap' (Gecko part).
1434478 part 1 - [css-grid] Stop back-computing percentage grid gaps when the percentage basis is indefinite. Treat them as zero sized instead.
1434478 part 2 - Stop back-computing percentage padding/margin when the percentage basis is indefinite. Treat them as zero sized instead.
1434478 part 3 - Remove IntrinsicISizeOffsetData::hPctPadding/hPctMargin members since they are now unused.
1434478 part 4 - Factor out constants like NS_UNCONSTRAINEDSIZE so they can be used in headers without needing nsIFrame.h (idempotent patch).
1434478 part 5 - Create nsLayoutUtils::ResolveToLength for resolving CSS <length-percentage> (idempotent patch).
1434478 part 6 - Propagate a percentage basis to nsIFrame::IntrinsicISizeOffsets for resolving padding/margin.
This is needed only for CSS Grid since in other cases we're only using IntrinsicISizeOffsets in the inline-axis and the percentage basis is always indefinite for *intrinsic sizing*. When calculating the intrinsic size of grid items in the grid container's block axis however, we do have a definite size for the grid area in the inline-axis and it should be used per: https://drafts.csswg.org/css-grid/#algo-overview "2. Next, the track sizing algorithm resolves the sizes of the grid rows, using the grid column sizes calculated in the previous step." (Percentage padding/margin for grid items is always resolved against the grid area's inline-size nowadays.)
win7-7
wolfbeast
Gaming4JC
Matt A. Tobin