use_concatenated_impulse_responses required for grit

build/secondary/tools/grit/grit_rule.gni

 # 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.
 
 # Instantiate grit. This will produce a script target to run grit, and a
 # static library that compiles the .cc files.
 #
 # Parameters
 #
 #   source (required)
@@ skipping 61 matching lines @@
 #     outputs = [
 #       "foo_strings.h",
 #       "foo_strings.pak",
 #     ]
 #
 #     grit_flags = [ "-E", "foo=bar" ]  # Optional extra flags.
 #     # You can also put deps here if the grit source depends on generated
 #     # files.
 #   }
 import("//build/config/chrome_build.gni")
+import("//third_party/WebKit/Source/config.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 
 grit_defines = []
 
 # Mac and iOS want Title Case strings.
 use_titlecase_in_grd_files = is_mac || is_ios
 if (use_titlecase_in_grd_files) {
   grit_defines += [
@@ skipping 151 matching lines @@
     "enable_settings_app",
   ]
 }
 if (enable_google_now) {
   grit_defines += [
     "-D",
     "enable_google_now",
   ]
 }
 
-# Note: use_concatenated_impulse_responses is omitted. It is never used and
-# should probably be removed from GYP build.
+if (use_concatenated_impulse_responses) {
+  grit_defines += [
+    "-D",
+    "use_concatenated_impulse_responses",
+  ]
+}
+
 if (enable_webrtc) {
   grit_defines += [
     "-D",
     "enable_webrtc",
   ]
 }
 if (enable_hangout_services_extension) {
   grit_defines += [
     "-D",
     "enable_hangout_services_extension",
@@ skipping 208 matching lines @@
     if (defined(invoker.configs)) {
       configs += invoker.configs
     }
 
     if (defined(invoker.visibility)) {
       visibility = invoker.visibility
     }
     output_name = grit_output_name
   }
 }