ozone_demo will not work under the new mojo-based plumbing for display configuration on Chrome OS.

When run with the legacy chrome IPC based plumbing, ozone_demo creates a fake "GPU process" via the helper class OzoneGpuTestHelper.

All this class does is route messages between the display configuration code (gpu process) and the window management code (browser process); a separate GPU process is not actually required and most of the platform code is unaware of whether one is used.

We should make ozone_demo work under the mojo plumbing so we can fully deprecate the chrome IPC plumbing.