Front components run in a Web Worker with a fake DOM. Until now the
worker had a hand-rolled `style` object for remote elements and the host
had its own separate CSS-string parser: two implementations of the same
parsing that kept drifting apart (several review rounds fixed edge cases
in one copy but not the other).
What changed:
- One shared `createStyleProxy` now backs `element.style` in the worker,
and one shared `parseCssDeclarations` feeds both the worker proxy and
the host's `parseCssString`. Most of the diff is existing logic split
out of `installStylePropertyOnRemoteElements` into small single-purpose
utils (`splitCssDeclarations`, `stripImportantPriorityFromCssValue`,
`normalizeCssPropertyName`, `formatCssValue`, ...), not new behavior.
- `!important` is stripped from values instead of tracked. Nothing ever
read priorities back, and the host applies styles through React inline
styles, which cannot express `!important`. Rendering note: `color: red
!important` used to reach React as an invalid value (property silently
not applied); it now applies, without the priority.
- Style writes flush to the host synchronously, exactly as on main.
- The parser handles quotes, escapes and parentheses; CSS comments
inside hand-written `cssText` are not supported.
This shared proxy is also the base for the worker `getComputedStyle`
stub in the geometry PR. Second of three PRs splitting the geometry
mirror work.
Raphaël Bosi
b8e2a6e910