Display a '+' icon on the provider icon if there are more results that are
hidden. If the provider icon is clicked, ask the provider to launch itself and
perform a search with the current terms.
https://bugzilla.gnome.org/show_bug.cgi?id=681797
The searchProvider interface originally used a GetResultMeta method to
return meta data of a single id; when it was changed to GetResultMetas,
the return value was not updated accordingly.
https://bugzilla.gnome.org/show_bug.cgi?id=683482
Add an asynchronous search provider for results from a DBus service
implementing the org.gnome.Shell.SearchProvider interface; this
will allow applications to hook into the Shell's search without
implementing it in Shell itself or requiring an extension.
https://bugzilla.gnome.org/show_bug.cgi?id=663125
