There's a wait of ~350ms on some machines between clicking on the animation and until it starts.
That seems to be related to overhead created when constructing the GraphicsLayer scene.
Created attachment 53981 [details]
make GraphicsLayerQt manage the cache itself instead of using QGraphicsItem::cache
Created attachment 53995 [details]
Fixed a problem in the first patch. Tested with all relevant LayoutTests
Created attachment 53996 [details]
Comment on attachment 53996 [details]
Clearing flags on attachment: 53996
Committed r58190: <http://trac.webkit.org/changeset/58190>
All reviewed patches have been landed. Closing bug.
Revision r58190 cherry-picked into qtwebkit-2.0 with commit 991f4f6002271f4f98cf6a9057184bf3954a1d0c