ozone/wayland: |data_device_| might be null

Fix crash that happens in tests if there is no data_device_.

PS: we don't have tests running in our bot yet. This is what I
observer, when did first runs locally.

Bug: 578890
Change-Id: I6b9b01fb1f29b71f6fb459b9c69d4967cbb99b95
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2062441
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Antonio Gomes <tonikitoo@igalia.com>
Cr-Commit-Position: refs/heads/master@{#743003}
1 file changed