Adding reference to experimental browser distribution files.

chrome/installer/installer.gyp

Index: chrome/installer/installer.gyp
===================================================================
--- chrome/installer/installer.gyp	(revision 25950)
+++ chrome/installer/installer.gyp	(working copy)
@@ -31,10 +31,6 @@
           'include_dirs': [
             '../..',
           ],
-          'variables': {
-            'extra_installer_util_sources%': [
-            ],
-          },
           'sources': [
             'util/browser_distribution.cc',
             'util/browser_distribution.h',
@@ -88,8 +84,19 @@
             'util/work_item_list.h',
             '../common/json_value_serializer.cc',
             '../common/pref_names.cc',
-            '<@(extra_installer_util_sources)',
           ],
+          'variables': {
+            'extra_installer_util_sources%': 0,
+          },
+          'conditions': [
+            ['extra_installer_util_sources', {
+                'sources': [
+                  'util/exp/experimental_browser_distribution.cc',
+                  'util/exp/experimental_browser_distribution.h',
+                ],
+              },
+            ],
+          ],
         },
         {
           'target_name': 'gcapi_dll',