Gets the OAuth2Based instance for the D-Bus interface <link linkend="gdbus-interface-org-gnome-OnlineAccounts-OAuth2Based.
top_of_page">org.gnome.OnlineAccounts.OAuth2Based</link> on this, if any.
| this |
A Object. |
|
A OAuth2Based that must be freed with unref or null if this does not implement the interface. |