Previously, during grid track maximization we used the total number of
grid tracks as the denominator when distributing the available free
space. Using a larger denominator than expected meant that the
algorithm needed a larger number of iterations than necessary to
converge leading to rounding errors in the final track sizes.
Implement the `dense` keyword for `grid-auto-flow` so auto-placed items
backfill earlier gaps in the grid. The sparse/dense cursor logic is now
centralized in `place_grid_items()` step 4: dense resets the cursor to
the grid start before each search, while sparse keeps advancing forward.
Also fix a pre-existing bug where `find_unoccupied_place()` and several
placement helpers only checked if a single cell was unoccupied, ignoring
multi-cell spans. Add `OccupationGrid::is_area_occupied()` and use it
throughout to correctly verify the entire rectangular area is available.
When `elementFromPoint()` or `elementsFromPoint()` returns an element
that is inside a UA internal shadow root, we now return the shadow host
for that element.
This change is currently entirely undetectable because of what the
added FIXME talks about. Currently, the HTML element's overflow is
always set to visible in both axes, so it getting set to "clip" in
the imported test ends up not mattering at all.
This commit includes two interdependent changes that must be applied
together:
- Treat `fit-content()` tracks as having an intrinsic min sizing
function when the limit resolves to zero.
- When clamping growth limit to fit-content limit, use `max(base_size,
fit_content_limit)` instead of just `fit_content_limit` to preserve
intrinsic sizing contributions.
These changes are coupled because the first change causes
`fit-content(0)` tracks to participate in intrinsic sizing, while the
second ensures the base size from that sizing is not discarded during
clamping.
Some subtests changed in response to this CSSWG resolution:
https://github.com/w3c/csswg-drafts/issues/11494#issuecomment-2675800489
Basically, `border-style: none` now affects the used value of
`border-width`, not the computed value. (And the same for `outline`
properties.)
This affects way more tests than I expected because
interpolation-testcommon.js now adds tests for composition.
