It breaks painting when the compositing layer has tiled layering.
This is a workaround until bug 134947 gets fixed.
Created attachment 234963 [details]
Created attachment 234964 [details]
Comment on attachment 234964 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=234964&action=review
> + When the compositing layer has tiled layering, offsetting the cliprect with the subpixel accumulation
"has tiled layering" -> "is tiled".
> + leaves a line of one device pixel gap on the non-leftmost tiles. It's because leftmost tiles get
leaves single device-pixel gap
> + // FIXME: Moving the cliprect by subPixelAccumulation requires to get IntRect enclosing removed from clipping/dirtyPaintRect.
"requires removal of the enclosingIntRect code from..."
> + if (!paintingInfo.subPixelAccumulation.isEmpty())
> + adjustedClipRect.expand(paintingInfo.subPixelAccumulation);
I'm not sure I agree with this expanding here. You're fixing a bug specific to tiled layers with a change that affects clipping in all composited layers, and may actually result in incorrect clipping.
Created attachment 235030 [details]
Comment on attachment 235030 [details]
Clearing flags on attachment: 235030
Committed r171165: <http://trac.webkit.org/changeset/171165>
All reviewed patches have been landed. Closing bug.