Move some global feature defines to buildflags

chrome/browser/resources/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("//chrome/common/features.gni")
 import("//tools/grit/grit_rule.gni")
 
 grit("net_internals_resources") {
   source = "net_internals_resources.grd"
   use_qualified_include = true
@@ skipping 70 matching lines @@
     "$root_out_dir/resources/extension/demo/library.js",
   ]
 }
 
 if (!is_ios) {
   grit("component_extension_resources") {
     source = "component_extension_resources.grd"
 
     # TODO(thestig): use_qualified_include = true
     defines = chrome_grit_defines
+    if (enable_hangout_services_extension) {
+      defines += [ "enable_hangout_services_extension" ]
+    }
+
     outputs = [
       "grit/component_extension_resources.h",
       "grit/component_extension_resources_map.cc",
       "grit/component_extension_resources_map.h",
       "component_extension_resources.pak",
     ]
     output_dir = "$root_gen_dir/chrome"
   }
 
   grit("settings_resources") {
@@ skipping 47 matching lines @@
     source = "sync_file_system_internals_resources.grd"
     use_qualified_include = true
     defines = chrome_grit_defines
     outputs = [
       "grit/sync_file_system_internals_resources.h",
       "sync_file_system_internals_resources.pak",
     ]
     output_dir = "$root_gen_dir/chrome"
   }
 }