After rebooting, I took a look at
/var/log/syslog and saw that there had been a GPU hang. Some web searching led me to a known bug that described the problem and some workarounds. I pieced together the solution from several comments on the bug: it involves installing a 3.19 Ubuntu kernel and a cutting edge X server.
First, fetch and install a recent kernel (note that the wget commands are split into two lines for clarity):
mkdir /tmp/kernel cd /tmp/kernel wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.19.3-vivid/\ linux-headers-3.19.3-031903-generic_3.19.3-031903.201503261036_amd64.deb wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.19.3-vivid/ linux-headers-3.19.3-031903_3.19.3-031903.201503261036_all.deb wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.19.3-vivid/\ linux-image-3.19.3-031903-generic_3.19.3-031903.201503261036_amd64.deb sudo dpkg -i linux-image* sudo dpkg -i linux-headers*
Then install the cutting edge X server:
sudo apt-add-repository ppa:xorg-edgers/ppa sudo apt-get update sudo apt-get dist-upgrade
Finally, reboot the system and verify that you are running kernel 3.19 and Mesa 10.6:
uname -r dpkg -l libgl1-mesa-dri
After this, visiting the Chrome site should not cause the screen to go black.