Move some global feature defines to buildflags

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("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 3927 matching lines @@
 
 proto_library("resource_prefetch_predictor_proto") {
   sources = [
     "predictors/resource_prefetch_predictor.proto",
   ]
 }
 
 grit("resources") {
   source = "browser_resources.grd"
   use_qualified_include = true
+
   defines = chrome_grit_defines
+  if (enable_hangout_services_extension) {
+    defines += [ "enable_hangout_services_extension" ]
+  }
+
   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 327 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }