Chrome Version: 65.0* (master, latest)
Chrome OS Platform: Linux/Ubuntu

Steps To Reproduce:
(1) Set up build environment following instruction at
https://chromium.googlesource.com/chromium/src/+/master/docs/linux_build_instructions.md
(2) Run "gn args" and configure target OS to ChromeOS.
> target_os = "chromeos"
(3) Build and run the chrome binary.

Expected Result:
The UI window shows up.

Actual Result:
The executable keeps running, but the UI window doesn't show up.