The attached testcase changes 'visibility' in the middle of an accelerated animation; this causes the element to jump around incorrectly.
<rdar://problem/7269294>
Created attachment 40479 [details] Testcase
The issue here is that we're setting animations on GraphicsLayer that are not in the tree, because the RenderLayer z-order list logic does not include layers with visiblility:hidden. And because the layers are not in the tree, we get no started callback, so this breaks all subsequent animation (see bug 26770).
Created attachment 41070 [details] Patch
Created attachment 41249 [details] WIP patch Stashing work in progress here. There are still a number of issues with this patch.
*** Bug 64166 has been marked as a duplicate of this bug. ***
Some visibility issues fixed by the patch in bug 38829.
Created attachment 112934 [details] Patch
Comment on attachment 112934 [details] Patch r=me
http://trac.webkit.org/changeset/98776
This caused lots of assertions, rolling out.
This patch has a problem. RenderLayerCompositor::computeCompositingRequirements() calls updateBacking() which can enter compositing mode. This happens in the middle of walking layers via the z-order tree, but invalidates the z-order trees. Oops.
For iframes and video we may make them compositing during computeCompositingRequirements(), not just as a result of RenderLayer::styleChanged.
Was it rolled out? I don't see a rollout revision on the bug.
It was, not sure why sheriffbot didn't note that here. Rollout was bug 71164.