If we notify the parent process about new child documents before we
notify it of events it is possible the parent process's tree is out of
sync with ours, and doesn't contain the outer doc accessible for the new
document. SO we need to first notify the parent of changes in the
accessible tree for the document, and then we can notify it of new child
documents. We must also make sure when we serialize a subtree that is
being created to not include the sub document or its accessible tree.
