Backport of "gst: Add support for g_autoptr(GstPromise)" into 1.16
Backport of !144 (merged) "gst: Add support for g_autoptr(GstPromise)".
Commits:
- cfca53ce gst: Add support for g_autoptr(GstPromise)
Backport of !144 (merged) "gst: Add support for g_autoptr(GstPromise)".
Commits: