for background, see https://bugs.webkit.org/show_bug.cgi?id=27425
this is notes to whomever implements DATAGRID for the Gobject bindings.
a patch has been accepted which includes a FIXME workaround which disables attempts to use code which the CodeGeneratorGObject.pm does not create (GdomHTMLDataGridElement.cpp,h; GdomHTMLDataGridRowElement.cpp,h) which in turn rely on code which also does not exist (GdomDataGridDataSource.cpp,h).
WebCore/bindings/gdom/GdomDataGridDataSource.cpp,h will need to be created by copying cut/paste style WebCore/bindings/js/JSDataGridDataSource.cpp,h and also working out why there is a custom WebCore/bindings/js/JSCustomHTMLDataGridColumnElement.cpp, and whether that needs to be copied cut/paste style to create WebCore/bindings/gdom/GdomCustomHTMLDataGridColumnElement.cpp.
also it may be necessary to add a toGDOM function to WebCore/bindings/gdom/GDOMBinding.cpp for the DataGridDataSource base class.
see also gdom.h which has #ifdef'd code for DATAGRID
Not sure if this is valid any longer. Feel free to re-open if I'm wrong.