The determineRenderSlider() convenience function added in bug 87551 made an assumption that wasn't always true. This didn't cause a functional error but it caused an assertion failure, which indicates a problem with the code.
Created attachment 146578 [details] Patch
Comment on attachment 146578 [details] Patch Clearing flags on attachment: 146578 Committed r119838: <http://trac.webkit.org/changeset/119838>
All reviewed patches have been landed. Closing bug.
Closing bug for patch that landed a long time ago.