We should add a testcase that exercises the logic in the FILL_UNSET_PROPERTY macro for animations/transitions.
Created attachment 25483 [details] Testcase Here's the testcase. It currently crashes.
Also, I think this testcase should live in LayoutTests/animations, and not css3/
Created attachment 25507 [details] Specific test for empty/single-key keyframes
Created attachment 25508 [details] Patch, including LayoutTest files Fix for a null deref bug. I was not checking for 0 length keyframe lists. This patch includes both tests added to this bug.
Fixed: http://trac.webkit.org/changeset/38776