Add ozone_unittests to the build.

R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/1331913004 .
diff --git a/BUILD.gn b/BUILD.gn
index 6f8bbd0..e314516 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -33,6 +33,7 @@
     deps += [
       "//ui/ozone",
       "//ui/ozone/demo",
+      "//ui/ozone:ozone_unittests",
     ]
   }
 }
diff --git a/ui/ozone/BUILD.gn b/ui/ozone/BUILD.gn
index f659df1..5d3724f 100644
--- a/ui/ozone/BUILD.gn
+++ b/ui/ozone/BUILD.gn
@@ -47,6 +47,7 @@
     "platform/drm:drm_common",
     "platform/drm:gbm",
   ]
+  ozone_platform_test_deps += [ "platform/drm:drm_unittests" ]
 }
 
 platform_list_cc_file = "$target_gen_dir/platform_list.cc"
diff --git a/ui/ozone/platform/drm/BUILD.gn b/ui/ozone/platform/drm/BUILD.gn
index 91cf91c..e530fac 100644
--- a/ui/ozone/platform/drm/BUILD.gn
+++ b/ui/ozone/platform/drm/BUILD.gn
@@ -156,7 +156,9 @@
       "//ui/events/ozone:events_ozone_layout",
     ]
   }
+}
 
+if (ozone_platform_dri || ozone_platform_drm || ozone_platform_gbm) {
   source_set("drm_unittests") {
     testonly = true
     sources = [
@@ -171,8 +173,10 @@
 
     deps = [
       "//base",
+      "//mojo/public/c/system:for_shared_library",
       "//skia",
       "//testing/gtest",
+      "//ui/ozone",
       "//ui/ozone:ozone_base",
       "//ui/ozone/platform/drm:drm_common",
     ]