Load http://slides.html5rocks.com/#slide39 and play with the box-shadow sliders. Note how the numbers next to the sliders fail to update when moving the slider thumb. However, we do move the slider around as if we were doing layout.
The text-shadow sliders work OK.
This only happens in the two-column configuration. If I disable the -webkit-column-count: 2; property, I don’t see the problem.
Created attachment 64886 [details]
The issue is that 'repaintTop', returned by layoutInlineChildren(), doesn't take columns into account.
Ah, this would be:
// FIXME: Deal with multiple column repainting. We have to split the repaint
// rect up into multiple rects if it spans columns.
Created attachment 64899 [details]
Comment on attachment 64899 [details]
Going to update this based on feedback from hyatt.
Created attachment 64966 [details]