Previously, getComputedStyle() would always call update_layout() for
most properties. This was expensive since layout involves a full tree
traversal even when only style information is needed.
This change introduces a more granular approach:
- Properties needing layout computation (used values like width/height)
still call update_layout()
- Properties needing a layout node for resolved value computation
(colors, border widths, etc.) also call update_layout()
- All other properties now only call update_style()
The set of properties needing layout node for resolution is now defined
in Properties.json via the "needs-layout-node-for-resolved-value" flag,
rather than being hardcoded. This is generated into a new function
property_needs_layout_node_for_resolved_value().
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.
This change adds the allowed angle range to the `font-style` property
definition. This allows these angles to be clamped after interpolation.
Ideally, the generator should be updated so that we can specify the
angle is in degrees. This would allow us to make use of this
information during parsing, which we can't do currently because we
don't know what the unit is. Using this value for interpolation
purposes is fine because the angle has been converted to its canonical
unit by this point.
Remaining test failures in font-size-interpolation-00* are either:
- Rounding of font-size to CSSPixels when setting the expected value
- Not clamping negative values from the point of view of
getComputedStyle (used values are still clamped)
Previously if we would overwrite the non-animated font-size with the
animated font-size if it was set.
Gains us 8 WPT tests and means we now fail 9 others in line with other
browsers.
`font-size` can end up with a negative value - either due to `calc`
being resolved using the old method which doesn't clamp the value, or
interpolation - in this case we should clamp negative values to zero.
Gains us 36 new WPT passes and fixes crashes in the three imported
tests.
