Chrome and Firefox inflate this rect to accommodate for the font's
ascenders and descenders, while the absolute rect for the fragment
remains unaffected. This fixes ascenders/descenders in text being
clipped when selecting text.
We were mimicking Firefox' behavior that whenever a programmatic change
to an <input>'s or <textarea>'s selection happened, the new selection
focus is brought into view by scrolling. Currently we run a layout
update synchronously for that to make sure we have the fragment's
correct dimensions, which caused a significant performance regression in
Speedometer.
Since this is non-standard behavior, let's mimic Chromium instead which
does not scroll at all - only for direct user initiated input such as
typing.
Relevant issues:
* https://github.com/whatwg/html/issues/6217
* https://bugzilla.mozilla.org/show_bug.cgi?id=232405
* https://issues.chromium.org/issues/41081857
The find_source_record lambda was doing a reverse linear scan through
the entire source map for every instruction emitted, resulting in
quadratic behavior. This was catastrophic for large scripts like
Octane/mandreel.js, where compile() dominated the profile at ~30s.
Since both source map entries and instruction iteration are ordered by
offset, replace the per-instruction scan with a forward cursor that
advances in lockstep with instruction emission.
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.
We should decide at a later stage, when we've calculated the final
background painting area, whether that area is empty and we can skip
painting the background.
Fixes#7973
PropertyKey values can only be String or Symbol per spec; numeric keys
are an internal optimization and should be treated as Strings.
This fixes incorrect behavior for numeric property names on legacy
platform objects (e.g. Web Storage).
Instead of copying the Bitmap that wraps the IOSurface, we can just
present the IOSurface directly. This significantly reduces CPU usage in
the UI process, particularly at high refresh rates such as 120Hz where
it would saturate a full CPU core.
This is done by using CAMetalLayer and blitting the IOSurface to the
next drawable buffer, which handles triple buffering, locking the
IOSurface and vsync automatically. This also allows the Metal HUD to
work, but the only accurate stat is the frame intervals/FPS because
it's in the UI layer, not WebContent. However, that's still useful
to detect frame drops.
Previously, case-insensitive regex matching used ASCII-only case
conversion (to_ascii_lowercase) even for Unicode characters.
Now we implement Canonicalize abstract operation, so we can case-fold
Unicode characters properly during case-insensitive matching.
This means we don't need to include `FilterValueListStyleValue.h` in as
many places - reducing the rebuild from editing that file from 717 files
to 19.
