Failed to run Content Shell: Content Shell failed with exit code 1..
Running the tests directly in content_shell (which pops up a GUI window) worked. Finally ran it with -`-dump-render-tree` and realized I was missing a few things:
sudo ln -sf /lib/$(arch)-linux-gnu/libudev.so.1 /lib/$(arch)-linux-gnu/libudev.so.0
sudo apt-get install ttf-kochi-gothic \
With that, my #dartlang tests are passing again :)