Introduce a new GstVaapiPluginBase object that will contain all common
data structures and perform all common tasks. First step is to have a
single place to hold VA displays.
While we are at it, also make sure to store and subsequently release
the appropriate debug category for the subclasses.
Use GstVaapiUploader helper that automatically handles direct rendering
mode, thus making the "direct-rendering" property obsolete and hence it
is now removed.
The "direct-rendering" level 2, i.e. exposing VA surface buffers, was never
really well supported and it could actually trigger degraded performance.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
