Use precompiled headers for most large projects.

chrome/installer/upgrade_test.gyp

 # 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.
 
 {
   'variables': {
     'version_py': '../../chrome/tools/build/version.py',
     'version_path': '../../chrome/VERSION',
     'lastchange_path': '<(SHARED_INTERMEDIATE_DIR)/build/LASTCHANGE',
     # 'branding_dir' is set in the 'conditions' section at the bottom.
     'msvs_use_common_release': 0,
     'msvs_use_common_linker_extras': 0,
   },
+  'includes': [
+    '../../build/win_precompile.gypi',
+  ],
   'conditions': [
     ['OS=="win"', {
       'targets': [
         {
           'target_name': 'alternate_version_generator_lib',
           'type': 'static_library',
           'dependencies': [
             '../chrome.gyp:common_constants',
             '../chrome.gyp:installer_util',
             '../../base/base.gyp:base',
@@ skipping 60 matching lines @@
       'variables': {
          'branding_dir': '../app/theme/google_chrome',
       },
     }, { # else branding!="Chrome"
       'variables': {
          'branding_dir': '../app/theme/chromium',
       },
     }],
   ],
 }