https://trac.webkit.org/changeset/270224/webkit broke the non-unified build because the BuildingState struct was defined in a cpp file. It references PositioningContext which is a class defined in that same file. Move it out into its own set of files.
Created attachment 415027 [details] WIP Patch
Comment on attachment 415027 [details] WIP Patch Just need a TreeBuilder::~TreeBuilder() = default in the cpp file.
Fixed more simply in r270251.