Commit 148300 introduced a new better was of restarting GIF animations after they have been suspended. Unfortunately the method did not get called on normal resumeActiveDOMObjectAndAnimations calls, but only when a page was returned from background.
Created attachment 207649 [details]
Comment on attachment 207649 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=207649&action=review
> + REGRESSION(148300) GIfs not reanimated after resumeActiveDOMObjectAndAnimations
Committed r153431: <http://trac.webkit.org/changeset/153431>