Add place holder to move gfx::Display/Screen to ui/display

ui/display/screen.h

Index: ui/display/screen.h
diff --git a/ui/display/screen.h b/ui/display/screen.h
new file mode 100644
index 0000000000000000000000000000000000000000..d7f2cab16ce20bef04aff52b958ed39c9996d66e
--- /dev/null
+++ b/ui/display/screen.h
@@ -0,0 +1,19 @@
+// 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.
+
+#ifndef UI_DISPLAY_SCREEN_H_
+#define UI_DISPLAY_SCREEN_H_
+
+#include "ui/gfx/screen.h"
+
+namespace display {
+
+// TODO(oshima): move the gfx::Screen to display::Screen.
+using Display = gfx::Display;
+using DisplayObserver = gfx::DisplayObserver;
+using Screen = gfx::Screen;
+
+}  // display
+
+#endif  // UI_DISPLAY_SCREEN_H_