We should match other all other browsers and remove the non-standard 'css'/'Css' prefixed properties on CSSStyleDeclaration, keeping only the standard 'cssFloat' (https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-cssfloat).
Created attachment 412265 [details] Patch
Created attachment 412268 [details] Patch
Created attachment 412270 [details] Patch
Created attachment 412278 [details] Patch
Committed r268962: <https://trac.webkit.org/changeset/268962> All reviewed patches have been landed. Closing bug and clearing flags on attachment 412278 [details].
<rdar://problem/70666307>
Re-opened since this is blocked by bug 218525
Created attachment 421682 [details] Patch
Committed r273592: <https://commits.webkit.org/r273592> All reviewed patches have been landed. Closing bug and clearing flags on attachment 421682 [details].