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().
The remaining failing tests in view-timeline-shorthand.html are due to
either:
a) incorrect tests, see web-platform-tests/wpt#56181 or;
b) a wider issue where we collapse coordinating value list longhand
properties to a single value when we shouldn't.
The remaining failing tests in scroll-timeline-shorthand.html are due to
either:
a) incorrect tests, see web-platform-tests/wpt#56181 or;
b) a wider issue where we collapse coordinating value list longhand
properties to a single value when we shouldn't.
This applies size, inline-size, and style containment in some cases.
There are other WPT tests for that, but we seem to not implement enough
of containment for this to have an effect so I've not imported those.
Gets us 35 WPT subtests.
This introduces the `TextUnderlinePositionStyleValue` class, it is
possible to represent `text-underline-position` as a `StyleValueList`
but would have required ugly workarounds for either serialization or in
`ComputedProperties::text_underline_position`
This property provides a hint to the rendering engine about properties
that are likely to change in the near future, allowing for early
optimizations to be applied.
Previously we would incorrectly map these in
`CSSStyleProperties::convert_declarations_to_specified_order`, aside
from being too early (as it meant we didn't maintain them as distinct
from their physical counterparts in CSSStyleProperties), this meant
that we didn't yet have the required context to map them correctly.
We now map them as part of the cascade process. To compute the mapping
context we do a cascade without mapping, and extract the relevant
properties (writing-direction and direction).
