Make it possible to disable dbus on linux

chrome/chrome_browser_extensions.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser_extensions',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 810 matching lines @@
             ['include', '^browser/extensions/api/web_request/web_request_permissions.cc'],
             ['include', '^browser/extensions/api/web_request/web_request_time_tracker.cc'],
           ],
           'dependencies!': [
             '../device/device.gyp:device_bluetooth',
             '../third_party/libusb/libusb.gyp:libusb'
           ],
         }],
         ['OS=="linux" and use_aura==1', {
           'dependencies': [
-            '../build/linux/system.gyp:dbus',
             '../build/linux/system.gyp:fontconfig',
             '../build/linux/system.gyp:x11',
-            '../dbus/dbus.gyp:dbus',
+          ],
+          'conditions': [
+            ['use_dbus==1', {
+              'dependencies': [
+                '../build/linux/system.gyp:dbus',
+                '../dbus/dbus.gyp:dbus',
+              ],
+            }],
           ],
         }],
         ['safe_browsing==1', {
           'defines': [
             'FULL_SAFE_BROWSING',
           ],
         }],
         ['safe_browsing==2', {
           'defines': [
             'MOBILE_SAFE_BROWSING',
           ],
         }],
         ['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',
           ],
+          'conditions': [
+            ['use_dbus == 1', {
+              'dependencies': [
+                '../build/linux/system.gyp:dbus',
+                '../dbus/dbus.gyp:dbus',
+              ],
+            }],
+          ],
         }],
         ['configuration_policy==1', {
           'dependencies': [
             'app/policy/cloud_policy_codegen.gyp:policy',
           ],
         }, {  # configuration_policy==0
           'sources!': [
             'browser/extensions/api/storage/managed_value_store_cache.cc',
             'browser/extensions/api/storage/managed_value_store_cache.h',
             'browser/extensions/api/storage/policy_value_store.cc',
@@ skipping 79 matching lines @@
           'variables': {
             'proto_in_dir': 'browser/chromeos/contacts',
             'proto_out_dir': 'chrome/browser/chromeos/contacts',
           },
           'includes': [ '../build/protoc.gypi' ]
         },
       ],
     },],  # 'chromeos=1'
   ],  # 'conditions'
 }