Why gnome_vfs_mime_get_extensions_list() returns NULL?

["brian.lu" <Brian Lu Sun COM>]

Hi, experts,

I'm investigating a firefox bug and I found that the root cause is that 
gnome_vfs_mime_get_extensions_list() returns NULL.
In firefox, gnome_vfs_mime_get_extensions_list() is called with 
"application/pdf" as a parameter.  It returns NULL.

I check the source code of gnome_vfs_mime_get_extensions_list() (which 
is contained in gnome-vfs-mime-info.c), it always returns
NULL.

Is the gnome_vfs_mime_get_extensions_list() deprecated?   If so,  can 
anyone tell me its replacement?

Thanks

Brian