The AtkDocument interface should be supported by any object whose content is a representation or view of a document.
The AtkDocument interface should appear on the toplevel container for the document content; however AtkDocument instances may be nested (i.e.
an AtkDocument may be a descendant of another AtkDocument) in those cases where one document contains "embedded content" which can reasonably be
considered a document in its own right.
The 'load-stopped' signal is emitted when a pending load of document
contents is cancelled, paused, or otherwise interrupted by the user or application logic.