GN: Get os="chromeos" use_ozone=true to compile

ui/ozone/gpu/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-group("demo") {
-  deps = [
-    ":ozone_demo",
+component("gpu") {
+  sources = [
+    "gpu_memory_buffer_factory_ozone_native_buffer.cc",
+    "gpu_memory_buffer_factory_ozone_native_buffer.h",
   ]
-}
 
-executable("ozone_demo") {
-  sources = [
-    "ozone_demo.cc",
-  ]
+  defines = [ "OZONE_GPU_IMPLEMENTATION" ]
 
   deps = [
     "//base",
-    "//skia",
+    "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
-    "//ui/ozone",
   ]
 }