Add DisplayCompositorTest.

services/ui/ws/BUILD.gn

Index: services/ui/ws/BUILD.gn
diff --git a/services/ui/ws/BUILD.gn b/services/ui/ws/BUILD.gn
index deca343d5ff0913bf61542c67c8d603cbf294b33..6671c95a0e29d35f37c444ca6851e11d8e60dfc7 100644
--- a/services/ui/ws/BUILD.gn
+++ b/services/ui/ws/BUILD.gn
@@ -197,6 +197,8 @@ group("tests") {
 
 test("mus_ws_unittests") {
   sources = [
+    # TODO(fsamuel): Move this test with DisplayCompositor. crbug.com/670454
+    "../surfaces/display_compositor_unittest.cc",
     "animation_runner_unittest.cc",
     "cursor_unittest.cc",
     "display_unittest.cc",
@@ -253,6 +255,9 @@ test("mus_ws_unittests") {
     "//ui/gl",
   ]
 
+  # TODO(fsamuel): Remove this dep. crbug.com/670454
+  deps += [ "//services/ui/surfaces" ]
+
   if (use_x11) {
     deps += [ "//tools/xdisplaycheck" ]
   }