Use precompiled headers for most large projects.

chrome/chrome.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': {
     'chromium_code': 1,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
       'version_path': 'VERSION',
@@ skipping 107 matching lines @@
         ],
       }],
     ],  # conditions
   },  # variables
   'includes': [
     # Place some targets in gypi files to reduce contention on this file.
     # By using an include, we keep everything in a single xcodeproj file.
     # Note on Win64 targets: targets that end with win64 be used
     # on 64-bit Windows only. Targets that end with nacl_win64 should be used
     # by Native Client only.
+    '../build/win_precompile.gypi',
     'app/policy/policy_templates.gypi',
     'chrome_browser.gypi',
     'chrome_common.gypi',
     'chrome_dll.gypi',
     'chrome_exe.gypi',
     'chrome_dll_syzygy.gypi',  # This must follow chrome_dll and chrome_exe.
     'chrome_installer.gypi',
     'chrome_installer_util.gypi',
     'chrome_renderer.gypi',
     'chrome_tests.gypi',
@@ skipping 1597 matching lines @@
             'destination': '<(PRODUCT_DIR)',
             'files': [
               '<(INTERMEDIATE_DIR)/repack/chrome.pak'
             ],
           },
         ],
       }],  # targets
     }],  # OS != "mac"
   ],  # 'conditions'
 }