When a page has an abs. pos. div at -1000px, -1000px, or uses text-indent: -9999px, then we should avoid making huge, tiled compositing layers to try to encompass these elements. More practically, this means constraining compositing layer size to the size of the enclosing document, or the enclosing overflow div.
<rdar://problem/8187624>
Created attachment 61609 [details] Patch
Comment on attachment 61609 [details] Patch Not yet ready for review. enclosingOverflowScrollAncestor() should look for any overflow/clipping, not just those that result in scrolling.
Comment on attachment 61609 [details] Patch s/convertContainerToLocalQuadI/convertContainerToLocalQuad
Created attachment 61701 [details] Patch
http://trac.webkit.org/changeset/63452
http://trac.webkit.org/changeset/63452 might have broken SnowLeopard Intel Release (Tests)