Set ozone_platform_wayland to true for ozone/ChromeOS builds

After [1], sysroots have the required dependencies installed
to get ozone/wayland builds going as part of the ozone/chromeos
buildbot - namely chromium_chromeos_ozone_rel_ng.

[1] https://codereview.chromium.org/2415933004/

BUG=295089

Review-Url: https://chromiumcodereview.appspot.com/2423833002
Cr-Commit-Position: refs/heads/master@{#426238}
diff --git a/ui/ozone/ozone.gni b/ui/ozone/ozone.gni
index d4a4307..629b75f 100644
--- a/ui/ozone/ozone.gni
+++ b/ui/ozone/ozone.gni
@@ -50,6 +50,7 @@
     } else if (is_chromeos) {
       ozone_platform_gbm = true
       ozone_platform_x11 = true
+      ozone_platform_wayland = true
     } else {
       # Build all platforms whose deps are in install-build-deps.sh.
       # Only these platforms will be compile tested by buildbots.