OSX and iOS don't support the non-separable blend modes (hue, saturation, color and luminosity).
The spec (http://dev.w3.org/fxtf/compositing-1/#mix-blend-mode) is currently in CR but will be updated.
Created attachment 230520 [details]
Attachment 230520 [details] did not pass style-queue:
ERROR: Source/WebCore/ChangeLog:11: You should remove the 'No new tests' and either add and list tests, or explain why no new tests were possible. [changelog/nonewtests] 
Total errors found: 1 in 10 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Created attachment 230524 [details]
Comment on attachment 230524 [details]
Clearing flags on attachment: 230524
Committed r168167: <http://trac.webkit.org/changeset/168167>
All reviewed patches have been landed. Closing bug.