I installed libgraphviz-dev 2.36.0-0ubuntu3.2 on Ubuntu GNOME 14.04 LTS. It installed libgvc6-plugin-gtk. I verified that libgvc6-plugin-gtk installed both libgvplugin_gdk.so.6.0.0 and libgvplugin_gtk.so.6.0.0.
In my terminal I ran
ls -lah /usr/lib/graphviz/
and all the files and symlinks looked correct.
I installed libgraphviz-dev 2.36.0-0ubuntu3.2 on Ubuntu GNOME 14.04 LTS. It installed libgvc6-plugin-gtk. I verified that libgvc6-plugin-gtk installed both libgvplugin_ gdk.so. 6.0.0 and libgvplugin_ gtk.so. 6.0.0.
In my terminal I ran
ls -lah /usr/lib/graphviz/
and all the files and symlinks looked correct.