current position should be ui-independent
@bilboed
Submitted by Edward Hervey Assigned to Edward Hervey @bilboed
Description
Currently the position of the current SmartBin played is queried in the UI (Viewer).
It should be up to the Playground to handle that and allow registration of callbacks that will be called when the position changes.
This should also avoid a lot of cruft currently in the UI.
Imported from https://bugzilla.gnome.org/show_bug.cgi?id=340382