If you use the animation shorthand without an animation-name and then use animation-name separately, the easing fallsback to the initial value (ease), instead of the specified one (linear). However, the shorthand declaration isn't dropped entirely, as the duration and iteration-count behave as expected.
Firefox does not have this problem, as can be seen by the more generic version of the testcase http://jsfiddle.net/leaverou/zXPzY/43/show (which uses -prefix-free to add the prefixes, unlike the testcase which only uses -webkit- and no scripts).
The issue is also reproducible in Webkit nightlies.
Created attachment 129511 [details]
Comment on attachment 129511 [details]
Attachment 129511 [details] did not pass chromium-ews (chromium-xvfb):
New failing tests:
Created attachment 129929 [details]
Proposed patch v2.
Comment on attachment 129929 [details]
Clearing flags on attachment: 129929
Committed r109610: <http://trac.webkit.org/changeset/109610>
All reviewed patches have been landed. Closing bug.
This apparently caused bug 84533.