Make it possible to disable dbus on linux

chrome/chrome_browser_ui.gypi

 # Copyright 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.
 
 {
   'targets': [
     {
       'target_name': 'browser_ui',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 2499 matching lines @@
         ['use_nss==0 and use_openssl==0', {
           'sources!': [
             'browser/ui/webui/certificate_viewer_webui.cc',
             'browser/ui/webui/certificate_viewer_webui.h',
             'browser/ui/webui/certificate_viewer_ui.cc',
             'browser/ui/webui/certificate_viewer_ui.h',
           ],
         }],
         ['toolkit_uses_gtk == 1', {
           'dependencies': [
-            '../build/linux/system.gyp:dbus',
             '../build/linux/system.gyp:gconf',
             '../build/linux/system.gyp:gtk',
             '../build/linux/system.gyp:gtkprint',
             '../build/linux/system.gyp:ssl',
             '../build/linux/system.gyp:x11',
             '../dbus/dbus.gyp:dbus',
             '../third_party/undoview/undoview.gyp:undoview',
           ],
         }],
+        ['use_dbus == 1', {
+          'dependencies': [
+            '../build/linux/system.gyp:dbus',
+          ],
+        }],
         ['enable_themes==0', {
           'sources!': [
             'browser/ui/webui/theme_source.cc',
           ],
         }],
         ['enable_printing!=1', {
           'sources/': [
             ['exclude', '^browser/ui/webui/print_preview/'],
           ],
         }],
@@ skipping 297 matching lines @@
         }],
         ['enable_message_center==1', {
           'dependencies': [
             '../ui/message_center/message_center.gyp:message_center',
           ],
         }],
       ],
     },
   ],
 }