They're already cached in the parsing stage so there's no sense in constructing new objects when exposing them through CSSComputedStyleDeclaration.
Created attachment 175862 [details]
Comment on attachment 175862 [details]
Clearing flags on attachment: 175862
Committed r135656: <http://trac.webkit.org/changeset/135656>
All reviewed patches have been landed. Closing bug.
(In reply to comment #2)
> (From update of attachment 175862 [details])
> Clearing flags on attachment: 175862
> Committed r135656: <http://trac.webkit.org/changeset/135656>
It made 2 tests crash on Qt, see https://bugs.webkit.org/show_bug.cgi?id=103196 for details.
Re-opened since this is blocked by bug 103218
This is not a valid optimization, since compute style values are exposed in CSSOM.