Enable precompiled headers for Blink on Windows

third_party/WebKit/Source/web/BUILD.gn

Index: third_party/WebKit/Source/web/BUILD.gn
diff --git a/third_party/WebKit/Source/web/BUILD.gn b/third_party/WebKit/Source/web/BUILD.gn
index 63e02806c0b455a699747ae9b6328fd7821fdd90..9851baa6feec45e0fa07464803b09d5fe79e5bde 100644
--- a/third_party/WebKit/Source/web/BUILD.gn
+++ b/third_party/WebKit/Source/web/BUILD.gn
@@ -1,6 +1,6 @@
 # Copyright 2014 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.
+# found in the LICENSE file.
 
 import("//build/config/ui.gni")
 import("//testing/test.gni")
@@ -33,6 +33,7 @@ component("web") {
 
   configs += [
     "//build/config/compiler:wexit_time_destructors",
+    "//third_party/WebKit/Source:blink_pch",
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:inside_blink",
     "//third_party/WebKit/Source:non_test_config",
@@ -79,7 +80,10 @@ source_set("test_support") {
     "WebTestingSupport.cpp",
   ]
 
-  configs += [ "//third_party/WebKit/Source:config" ]
+  configs += [
+    "//third_party/WebKit/Source:blink_pch",
+    "//third_party/WebKit/Source:config",
+  ]
 
   include_dirs = [ "$root_gen_dir/blink" ]
 }
@@ -133,6 +137,7 @@ test("webkit_unit_tests") {
   sources += platform_web_unittest_files
 
   configs += [
+    "//third_party/WebKit/Source:blink_pch",
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:inside_blink",
   ]