[ozone/wayland] Use FakeDisplayDelegate in order to make "off device" launch work

[1] introduced the "fake display" concept, updating OzonePlatformHeadless
and OzonePlatformX11 to use it, but not OzonePlatformWayland.
As a result, "chrome --mash --ozone-platform=wayland" fails to launch.

This CL fixes it by returning a FakeDisplayDelegate instance
in OzonePlatformWayland::CreateNativeDisplayDelegate, similarly
to other off-device capable ozone platforms.

[1] https://codereview.chromium.org/2324163002


Review-Url: https://codereview.chromium.org/2389053003
Cr-Commit-Position: refs/heads/master@{#423254}
1 file changed