This test used to assert because we tried to get frame geometry during a caret
update while the frame was dirty. That no longer happens since now we only try
to get frame geometry during a paint. During a paint, frames can still be dirty
so this assertion could still be triggered, and we should probably fix that
eventually, but it would only happen during an interrupted layout which is
quite rare.
--HG--
extra : rebase_source : a73866834119e5c617adb0a7757fde27d2791759
342293245c