Use precompiled headers for most large projects.

build/win_precompile.gypi

Index: build/win_precompile.gypi
diff --git a/build/win_precompile.gypi b/build/win_precompile.gypi
new file mode 100644
index 0000000000000000000000000000000000000000..90bcdff615b3e9e25e6dc1a42e00f9dc260b525b
--- /dev/null
+++ b/build/win_precompile.gypi
@@ -0,0 +1,20 @@
+# 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.
+
+# Include this file to make targets in your .gyp use the default
+# precompiled header on Windows.
+
+{
+  'conditions': [
+    # Restricted to VS 2010 until GYP also supports suppressing
+    # precompiled headers on .c files in VS 2008.
+    ['OS=="win" and (MSVS_VERSION=="2010" or MSVS_VERSION=="2010e")', {
+      'target_defaults': {
+        'msvs_precompiled_header': '<(DEPTH)/build/precompile.h',
+        'msvs_precompiled_source': '<(DEPTH)/build/precompile.cc',
+        'sources': ['<(DEPTH)/build/precompile.cc'],
+      },
+    }],
+  ],
+}