Use precompiled headers for most large projects.

build/common.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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 179 matching lines @@
 
       # Enable Web Intents and supporting UI.
       'enable_web_intents%': 0,
 
       # Smooth scrolling is disabled by default.
       'enable_smooth_scrolling%': 0,
 
       # Webrtc compilation is enabled by default. Set to 0 to disable.
       'enable_webrtc%': 1,
 
+      # Whether to use precompiled headers on Windows.
+      'use_precompiled_headers%': 0,
+
       'conditions': [
         # Use Skia as WebKit renderer on Mac
         ['OS=="mac"', {
           'use_skia%': 0,
         }, {
           'use_skia%': 1,
         }],
 
         # A flag for POSIX platforms
         ['OS=="win"', {
@@ skipping 85 matching lines @@
     'python_ver%': '<(python_ver)',
     'armv7%': '<(armv7)',
     'arm_neon%': '<(arm_neon)',
     'sysroot%': '<(sysroot)',
     'disable_sse2%': '<(disable_sse2)',
     'component%': '<(component)',
     'use_titlecase_in_grd_files%': '<(use_titlecase_in_grd_files)',
     'use_third_party_translations%': '<(use_third_party_translations)',
     'remoting%': '<(remoting)',
     'enable_webrtc%': '<(enable_webrtc)',
+    'use_precompiled_headers%': '<(use_precompiled_headers)',
     'p2p_apis%': '<(p2p_apis)',
     'configuration_policy%': '<(configuration_policy)',
     'safe_browsing%': '<(safe_browsing)',
     'clang_use_chrome_plugins%': '<(clang_use_chrome_plugins)',
     'enable_register_protocol_handler%': '<(enable_register_protocol_handler)',
     'enable_smooth_scrolling%': '<(enable_smooth_scrolling)',
     # Whether to build for Wayland display server
     'use_wayland%': 0,
 
     # The release channel that this build targets. This is used to restrict
@@ skipping 495 matching lines @@
           # Clang creates chubby debug information, which makes linking very
           # slow. For now, don't create debug information with clang.  See
           # http://crbug.com/70000
           ['OS=="linux" and clang==1', {
             'variables': {
               'debug_extra_cflags': '-g0',
             },
           }],
         ],  # conditions for fastbuild.
       }],  # fastbuild!=0
+      ['use_precompiled_headers!=0', {
+        'conditions': [
+          ['OS=="win"', {
+            'sources': ['<(DEPTH)/build/precompile.cc'],
+            'msvs_precompiled_header': '<(DEPTH)/build/precompile.h',
+            'msvs_precompiled_source': '<(DEPTH)/build/precompile.cc',
+          }],  # OS=="win"
+        ],  # conditions
+      }],  # use_precompiled_headers!=0
       ['selinux==1', {
         'defines': ['CHROMIUM_SELINUX=1'],
       }],
       ['win_use_allocator_shim==0', {
         'conditions': [
           ['OS=="win"', {
             'defines': ['NO_TCMALLOC'],
           }],
         ],
       }],
@@ skipping 1128 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }