Bug 301907 – [css-grid-3] Support 'display: masonry' so we can run WPT tests

• Component: CSS
• Status: RESOLVED FIXED

[fantasai]

The CSSWG resolved to use 'display' for switching into masonry-style layout, but hasn't decided on a keyword yet. However all the WPTs are using 'display: masonry', which means we need to support this syntax if we want to run the WPTs. We can update to the final keyword later.

[Radar WebKit Bug Importer]

<rdar://problem/163985106>

[fantasai]

Created attachment 477282 [details]
patch

A number of tests (21) are crashing on this line so can't record their results:

void GridMasonryLayout::placeMasonryItems(const GridTrackSizingAlgorithm& algorithm, GridMasonryLayout::MasonryLayoutPhase layoutPhase)
{
    ASSERT(m_gridAxisTracksCount);

For example https://wpt.live/css/css-grid/masonry/tentative/column-empty-masonry-container-001.html

[fantasai]

Created attachment 477301 [details]
patch

Rebased over main. Getting 91 tests crash now, all hitting a "not reached" assert in InlineItemsBuilder::collectInlineItems(). Sample of crashing tests:

imported/w3c/web-platform-tests/css/css-grid/masonry/tentative/alignment/masonry-align-content-001.html	
imported/w3c/web-platform-tests/css/css-grid/masonry/tentative/intrinsic-sizing/masonry-intrinsic-sizing-cols-002-auto.html	
imported/w3c/web-platform-tests/css/css-grid/masonry/tentative/item-placement/masonry-item-placement-003.html	
imported/w3c/web-platform-tests/css/css-grid/masonry/tentative/items/column-item-percentage-sizes-002.html	
imported/w3c/web-platform-tests/css/css-grid/masonry/tentative/track-sizing/auto-repeat/intrinsic-auto-repeat/row-auto-repeat-auto-006.html

[fantasai]

Pull request: https://github.com/WebKit/WebKit/pull/53460

[EWS]

Committed 302746@main (ec8a41f79f5b): <https://commits.webkit.org/302746@main>

Reviewed commits have been landed. Closing PR #53460 and removing active labels.