Make it possible to disable dbus on linux

chrome/chrome_browser_extensions.gypi

Index: chrome/chrome_browser_extensions.gypi
diff --git a/chrome/chrome_browser_extensions.gypi b/chrome/chrome_browser_extensions.gypi
index 5affe99bcb619b2d4752a8a9585cf0f212730313..29331a6f06e431a471b5fbbd40f580bc5bc18eb4 100644
--- a/chrome/chrome_browser_extensions.gypi
+++ b/chrome/chrome_browser_extensions.gypi
@@ -828,10 +828,16 @@
         }],
         ['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', {
@@ -846,15 +852,21 @@
         }],
         ['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': [