New build flag system, convert Google Now flag

chrome/browser/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/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
+import("//chrome/common/features.gni")
 import("//media/media_options.gni")
 import("//third_party/protobuf/proto_library.gni")
 
 # //build/config/android/rules.gni imports //tools/grit/grit_rule.gni, which
 # produces a conflict for the "grit" template so we have to only include one.
 if (is_android) {
   import("//build/config/android/rules.gni")
 } else {
   import("//tools/grit/grit_rule.gni")
 }
@@ skipping 931 matching lines @@
     if (enable_configuration_policy) {
       deps += [ "//chrome/browser/policy:path_parser" ]
     }
   }
 }
 
 # GYP version: chrome/chrome_resources.gyp:chrome_resources
 # (generate_browser_resources action)
 grit("resources") {
   source = "browser_resources.grd"
+  defines = chrome_grit_defines
   output_dir = "$root_gen_dir/chrome"
   outputs = [
     "grit/browser_resources.h",
     "browser_resources.pak",
   ]
 
   grit_flags = [
     "-E",
     "additional_modules_list_file=" +
         rebase_path(additional_modules_list_file, root_build_dir),
@@ skipping 303 matching lines @@
         rebase_path(gypi_values.chrome_browser_rlz_sources, ".", "//chrome")
     deps = [
       "//components/google/core/browser",
       "//components/omnibox/browser",
       "//components/rlz",
       "//components/search_engines",
       "//rlz:rlz_lib",
     ]
   }
 }