Do not define use_clipboard_aurax11 on ozone builds

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,
   },
   'targets': [
     {
@@ skipping 407 matching lines @@
                 ['include', '^base/dragdrop/os_exchange_data.cc'],
               ],
             }],
           ],
         }],
         ['use_pango==1', {
           'dependencies': [
             '../build/linux/system.gyp:pangocairo',
           ],
         }],
-        ['use_x11==0 or use_clipboard_aurax11==1', {
+        ['OS=="win" or use_clipboard_aurax11==1', {
           'sources!': [
             'base/clipboard/clipboard_aura.cc',
           ],
         }, {
           'sources!': [
             'base/clipboard/clipboard_aurax11.cc',
           ],
         }],
         ['chromeos==1 or (use_aura==1 and OS=="linux" and use_x11==0)', {
           'sources!': [
@@ skipping 252 matching lines @@
               'xcode_settings': {
                 'GCC_SYMBOLS_PRIVATE_EXTERN': 'NO',
               },
             }],
           ],
         },
       ],
     }],
   ],
 }