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

ui/display/display.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 53 matching lines @@
         'chromeos/x11/display_mode_x11.cc',
         'chromeos/x11/display_mode_x11.h',
         'chromeos/x11/display_snapshot_x11.cc',
         'chromeos/x11/display_snapshot_x11.h',
         'chromeos/x11/display_util_x11.cc',
         'chromeos/x11/display_util_x11.h',
         'chromeos/x11/native_display_delegate_x11.cc',
         'chromeos/x11/native_display_delegate_x11.h',
         'chromeos/x11/native_display_event_dispatcher_x11.cc',
         'chromeos/x11/native_display_event_dispatcher_x11.h',
+        'display.h',
         'display_export.h',
+        'display_observer.h',
         'display_switches.cc',
         'display_switches.h',
         'manager/display_layout.cc',
         'manager/display_layout.h',
         'manager/display_layout_builder.cc',
         'manager/display_layout_builder.h',
+        'screen.h',
         'win/display_info.cc',
         'win/display_info.h',
         'win/dpi.cc',
         'win/dpi.h',
         'win/screen_win.cc',
         'win/screen_win.h',
         'win/screen_win_display.cc',
         'win/screen_win_display.h',
       ],
       'conditions': [
@@ skipping 154 matching lines @@
             '../../build/isolate.gypi',
           ],
           'sources': [
             'display_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }