It's not possible to run mus_demo on a device right now. The ui service crashes in ui::Service::OnStart().

The problem is that Ozone DRM tries to use the TaskScheduler singleton but the singleton was never created. It's the same issue as  crbug.com/679840  I fixed earlier this week. However, I fixed the issue for things that started by MashRunner used by ./chrome --mash. This is different than what ./mash runner.

Here are some basic instructions to get all the necessary files on device, in case I forget.

# build mus_demo and mash/runner
ninja -C $BOARD services/ui/demo mash/runner

# rsync these files to your /opt/google/chrome on device
mash
mash_catalog.json
Packages/mus_demo/*
Packages/ui/*
Packages/tracing/*

# run mus_demo from terminal on device
./mash --service=mus_demo