Necessary after GTK_NOTE was replaced by GTK_DEBUG.
GTK_DEBUG is defined in gtk/gtkprivate.h. GTK_NOTE was defined
in gtk/gtkdebug.h.

Include gtkprivate.h for I_() and glib-i18n.h for
gettext macros.

This loop has many early exits, and all of them
need to free this info object that gets allocated
at the beginning.

Return code EAGAIN expects the user to feed more packets into the decoder

Those property features don't seem to be in use anywhere.
They are redundant since the docs cover the same information
and more. They also created unnecessary translation work.

Closes #4904

This seems to be a problem since:
https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/3565

To demo the problem, the video demo in gtk4-demo is currently set to
autoplay, but it doesn't autoplay on load as expected because the
"prepared" notification doesn't fire until the user explicitly presses
play.

Similarly if the demo is tweaked to disable autoplay then on loading a
video (or an audio-only ogg) the duration is not known or shown until
the user presses play.

In LibreOffice we want to know what the size of the video is to position
it before the user can interact with it to set it to play. We can
workaround this to some degree by listening to "invalidate-size" on the
GtkMediaStream object which updates for videos, but that doesn't wor
for audio-only streams.

So restore listening to media-info-updated but ignore -1 (which I see
for audio-only where I get -1 and then a useful value) and 0 of the
original report.

see also:
https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/3550

GNOME/gtk!4513