Aura on Linux: Make a DesktopScreenX11 to match the windows one.

ui/ui.gyp

 # Copyright (c) 2012 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,
   },
   'includes': [
     'ui_resources.gypi',
@@ skipping 358 matching lines @@
         'gfx/rect_base_impl.h',
         'gfx/render_text.cc',
         'gfx/render_text.h',
         'gfx/render_text_linux.cc',
         'gfx/render_text_linux.h',
         'gfx/render_text_win.cc',
         'gfx/render_text_win.h',
         'gfx/screen.h',
         'gfx/screen_android.cc',
         'gfx/screen_aura.cc',
-        'gfx/screen_aurax11.cc',
         'gfx/screen_gtk.cc',
         'gfx/screen_impl.h',
         'gfx/screen_mac.mm',
         'gfx/screen_win.cc',
         'gfx/scoped_cg_context_save_gstate_mac.h',
         'gfx/scoped_ns_graphics_context_save_gstate_mac.h',
         'gfx/scoped_ns_graphics_context_save_gstate_mac.mm',
         'gfx/scrollbar_size.cc',
         'gfx/scrollbar_size.h',
         'gfx/selection_model.cc',
@@ skipping 354 matching lines @@
                 'shutil.copyfile(\'<(ui_copy_target)\', \'<(ui_copy_dest)\'); ' \
                 'os.chmod(\'<(ui_copy_dest)\', 0700)'
               ]
             }
           ],
         },
       ],
     }],
   ],
 }