Add precompiled headers to GN build for large targets.

chrome/utility/BUILD.gn

 # 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.
 
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("../chrome_utility.gypi") ],
                           "scope",
                           [ "../chrome_utility.gypi" ])
 
 static_library("utility") {
   sources = rebase_path(gypi_values.chrome_utility_sources, ".", "..")
   defines = []
+  configs += [ "//build/config:precompiled_headers" ]
 
   public_deps = []
   deps = [
     "//base",
     "//components/safe_json:safe_json_parser_message_filter",
     "//components/search_engines",
     "//components/strings",
     "//components/url_fixer",
     "//content/public/common",
     "//content/public/utility",
@@ skipping 74 matching lines @@
     ]
   }
 
   if (!enable_mdns) {
     sources -= [
       "local_discovery/service_discovery_message_handler.cc",
       "local_discovery/service_discovery_message_handler.h",
     ]
   }
 }