Make a pre-read A/B field-trial

chrome/chrome_browser.gypi

 # Copyright (c) 2011 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',
       'type': 'static_library',
       'dependencies': [
@@ skipping 265 matching lines @@
         'browser/bookmarks/bookmark_service.h',
         'browser/bookmarks/bookmark_storage.cc',
         'browser/bookmarks/bookmark_storage.h',
         'browser/bookmarks/bookmark_utils.cc',
         'browser/bookmarks/bookmark_utils.h',
         'browser/bookmarks/recently_used_folders_combo_model.cc',
         'browser/bookmarks/recently_used_folders_combo_model.h',
         'browser/browser_about_handler.cc',
         'browser/browser_about_handler.h',
         'browser/browser_main.cc',
+        'browser/browser_main.h',
         'browser/browser_main_gtk.cc',
         'browser/browser_main_gtk.h',
         'browser/browser_main_mac.mm',
         'browser/browser_main_posix.cc',
         'browser/browser_main_posix.h',
         'browser/browser_main_win.cc',
         'browser/browser_main_win.h',
         'browser/browser_process.cc',
         'browser/browser_process.h',
         'browser/browser_process_impl.cc',
@@ skipping 4594 matching lines @@
       ],
       'export_dependent_settings': [
         'in_memory_url_index_cache_proto',
       ],
       # This target exports a hard dependency because it includes generated
       # header files.
       'hard_dependency': 1,
     },
   ],
 }