If vaapisink is in the GStreamer pipeline, then we shall allocate a
unique GstVaapiDisplay and propagate it upstream. i.e. subsequent
queries from vaapidecode shall get a valid answer from vaapisink.
Move display types from gstvaapipluginutil.* to gstvaapidisplay.* so that
we could simplify characterization of a GstVaapiDisplay. Also rename "auto"
type to "any", and add a "display-type" attribute.
vaapisink is now built with support for multiple display types, whenever
they are enabled. The new "display" attribute is used to select a particular
renderer.
This new interface allows for upstream and downstream display sharing
that works in both static and dynamic pipelines.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>