Because of the extra empty layer in the tree.
Created attachment 229181 [details] as-yet untested patch waiting on a build at the moment
Created attachment 229184 [details] patch
Created attachment 229188 [details] patch
http://trac.webkit.org/changeset/167177
The tree is still red, can you please have a look?
Wat, fixed the majority but there's one left? That is bizarre... I will look right away.
Reopening to fix the one remaining failure.
If we have a layer, skip one of its children, then want its grandchildren listed in its children's place, we won't correctly skip any grandchildren that want skipping. This mechanism (my fault in the first place, from many months ago) is a bit flawed. Will fix.
Created attachment 229268 [details] part 2
Comment on attachment 229268 [details] part 2 View in context: https://bugs.webkit.org/attachment.cgi?id=229268&action=review > Source/WebCore/platform/graphics/GraphicsLayer.cpp:596 > + for (size_t childIndex = 0; childIndex < children.size(); childIndex++) { > + GraphicsLayer* child = children[childIndex]; This should use a C++11 for loop: for (auto* child : children) {
http://trac.webkit.org/changeset/167246