Make DesktopFactoryOzone instances to respect --ozone-platform

ui/views/widget/desktop_aura/desktop_factory_ozone_wayland.cc

+// Copyright 2016 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.
+
+#include "ui/views/widget/desktop_aura/desktop_factory_ozone_wayland.h"
+#include <stdio.h>
+
+namespace views {
+
+DesktopWindowTreeHost* DesktopFactoryOzoneWayland::CreateWindowTreeHost(
+    internal::NativeWidgetDelegate* native_widget_delegate,
+    DesktopNativeWidgetAura* desktop_native_widget_aura) {
+  return nullptr;
+}
+
+display::Screen* DesktopFactoryOzoneWayland::CreateDesktopScreen() {
+  return nullptr;
+}
+
+views::DesktopFactoryOzone* CreateDesktopFactoryOzoneWayland() {
+  return new views::DesktopFactoryOzoneWayland;
+}
+
+}  // namespace views