As described on webkit-dev, new flag to implement improved animation engine (and maybe API).
<rdar://problem/15237054>
Created attachment 214322 [details] Patch
Could also you link the spec in your changelog? That would be useful for future references.
(In reply to comment #3) > Could also you link the spec in your changelog? That would be useful for future references. Will do, although we're not actually going to implement the spec just yet. This is purely an engine-internal feature for a fair while.
Committed r157479: <http://trac.webkit.org/changeset/157479>