Tries to guess the type of the tree with root
looking at the files it contains. The result is an array
of content types, with the best guess coming first.
The types returned all have the form x-content/foo, e.g. x-content/audio-cdda (for audio CDs) or x-content/image-dcf (for a camera memory card). See the shared-mime-info specification for more on x-content types.
This function is useful in the implementation of g_mount_guess_content_type().
Available since: 2.18
The root of the tree to guess a type for.
The data is owned by the caller of the function.