Go to: http://scarey.org/albums/lp and try to click on the album art to make it flip. The back cover flashes, then disappears. The front cover remains visible, rendered backward.
<rdar://problem/16878497>
When applying the transform to flip, we're not doing layout so not updating the "m_hasTransformedAncestor" flags.
Forcing layout when style changes between having a transform and not having one is not enough to fix this; we evaluate compositing at the start of the transition, when we've set the identity matrix on an ancestor (which will then animate to a 3D matrix).
Also have to deal with animations that go from 2D -> 3D matrix.
Created attachment 236148 [details] Patch
Attachment 236148 [details] did not pass style-queue: ERROR: Source/WebCore/rendering/RenderLayerCompositor.cpp:2395: Multi line control clauses should use braces. [whitespace/braces] [4] Total errors found: 1 in 5 files If any of these errors are false positives, please file a bug against check-webkit-style.
https://trac.webkit.org/r172183