Linux Aura accessibility is enabled only on GNOME desktops

ui/accessibility/accessibility.gyp

 # Copyright 2013 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 45 matching lines @@
         'platform/ax_platform_node_mac.mm',
         'platform/ax_platform_node_win.h',
         'platform/ax_platform_node_win.cc',
       ],
       'conditions': [
         ['OS=="win"', {
           'dependencies': [
             '../../third_party/iaccessible2/iaccessible2.gyp:iaccessible2'
           ],
         }],
+        ['OS=="linux" and chromeos==0 and use_gconf==1',{
+          'dependencies': [
+            '../../build/linux/system.gyp:gconf',
+          ],
+        }],
+        ['OS=="linux" and chromeos==0 and use_dbus==1', {
+          'dependencies': [
+            '../../build/linux/system.gyp:dbus',
+            '../../dbus/dbus.gyp:dbus',
+          ],
+        }],
         ['OS=="linux" and chromeos==0 and use_x11==1', {
           'dependencies': [
             '../../build/linux/system.gyp:atk',
-            '../../build/linux/system.gyp:gconf',
             '../../build/linux/system.gyp:glib',
           ],
           'variables': {
             'clang_warning_flags': [
               # glib uses the pre-c++11 typedef-as-static_assert hack.
               '-Wno-unused-local-typedefs',
             ],
           },
         }],
         ['OS!="linux" or chromeos==1 or use_x11==0', {
@@ skipping 97 matching lines @@
               'dependencies': [
                 '../../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }