[mime-data] Allow embedding of arbitrary mime-types.

Use the surface user-data array allow to store an arbitrary set of
alternate image representations keyed by an interned string (which
ensures that it has a unique key in the user-visible namespace).

Update the API to mirror that of cairo_surface_set_user_data() [i.e.
return a status indicator] and switch internal users of the mime-data to
the public functions.

1 files changed, 0 insertions, 0 deletions

diff --git a/test/romedalen.jpg b/test/romedalen.jpg
new file mode 100644
index 000000000..d655e3d89
--- /dev/null
+++ b/test/romedalen.jpg