Regarding the comment from darktears (https://bugs.webkit.org/show_bug.cgi?id=100058#c2), I'll move CSSPropertyWebkitTextAlignLast into isValidKeywordPropertyAndValue function like the same kind of properties.. This will help speed wise in JS.
Created attachment 174297 [details] Patch
Comment on attachment 174297 [details] Patch Clearing flags on attachment: 174297 Committed r135136: <http://trac.webkit.org/changeset/135136>
All reviewed patches have been landed. Closing bug.