Support layoutTestController.layerTreeAsText in WebKitTestRunner, this depends on bug 41084 (implementing accelerated compositing).
At least the following tests need it: compositing/geometry/clip.html compositing/geometry/preserve-3d-switching.html compositing/iframes/composited-parent-iframe.html compositing/iframes/connect-compositing-iframe2.html compositing/iframes/connect-compositing-iframe3.html compositing/iframes/connect-compositing-iframe-delayed.html compositing/iframes/connect-compositing-iframe.html compositing/iframes/enter-compositing-iframe.html compositing/iframes/iframe-resize.html compositing/iframes/iframe-size-to-zero.html compositing/iframes/overlapped-iframe.html compositing/iframes/scrolling-iframe.html compositing/images/clip-on-directly-composited-image.html compositing/layer-creation/overflow-scroll-overlap.html compositing/overflow/clip-descendents.html compositing/plugins/1x1-composited-plugin.html compositing/plugins/large-to-small-composited-plugin.html compositing/plugins/small-to-large-composited-plugin.html compositing/tiling/huge-layer-add-remove-child.html compositing/tiling/huge-layer-resize.html compositing/tiling/huge-layer-with-layer-children-resize.html compositing/tiling/huge-layer-with-layer-children.html compositing/tiling/huge-layer.html
<rdar://problem/8184408>
Created attachment 71917 [details] Patch
Comment on attachment 71917 [details] Patch Sweet.
http://trac.webkit.org/changeset/70548