The main reason is to differentiate when we have the GfxLink from
other (url, file) links which use the same terminology.

Change-Id: I805c61e7fb231062340562c51c25a189b2cfc7f7
Reviewed-on: https://gerrit.libreoffice.org/52245Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>