In Dev mode, drop into a shell and remove rootfs verification so we can copy files to wherever and then reboot
sudo /usr/share/vboot/bin/make_dev_ssd.ssh --remove_rootfs_verification
Now go back into shell, copy fonts over and reboot again
sudo cp *.ttf /usr/share/fonts/croscore/
Now you can go into Settings ->Under the Hood->Customize Fonts and you should see your font.
if your font is in a zip file, download and install unzip from http://www.duh.org/chromiumos/pkgs/
after following the steps to remove rootfs verification, you can install unzip using the following command:
sudo tar --wildcards -C / -xvjf /home/chronos/user/Downloads/unzip-6.0-r1.tbz2 './usr/local/*'
then you should be able to unzip your downloaded font using:
I realized i liked the new Ubuntu font much more than the new Chrome Tinos font and this spurred my interest in it!