r176212 added support for throttling specific DOMTimers that are updating the style of Element outside the viewport for performance reasons. However, it appears this change broke app switching on iCloud.com, hinting that such throttling may not be safe. Radar: <rdar://problem/21235277>
Created attachment 254375 [details] Patch
Don't you also need to revert some tests?
Comment on attachment 254375 [details] Patch Right! the tests...
Created attachment 254380 [details] Patch
Comment on attachment 254380 [details] Patch Clearing flags on attachment: 254380 Committed r185269: <http://trac.webkit.org/changeset/185269>
All reviewed patches have been landed. Closing bug.