WebUI: Vulcanize MD Settings at compile time.

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 76 matching lines @@
     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") {
-    source = "settings/settings_resources.grd"
+    if (use_vulcanize) {
+      source = "settings/settings_resources_vulcanized.grd"
+      deps = [
+        "//chrome/browser/resources/settings:build",
+      ]
+      grit_flags = [
+        "-E",
+        "root_gen_dir=" + rebase_path(root_gen_dir, root_build_dir),
+      ]
+    } else {
+      source = "settings/settings_resources.grd"
+    }
 
     # TODO(thestig): use_qualified_include = true
     defines = chrome_grit_defines
     outputs = [
       "grit/settings_resources.h",
       "grit/settings_resources_map.cc",
       "grit/settings_resources_map.h",
       "settings_resources.pak",
     ]
     output_dir = "$root_gen_dir/chrome"
@@ skipping 47 matching lines @@
     source = "webapks_ui_resources.grd"
     use_qualified_include = true
     defines = chrome_grit_defines
     outputs = [
       "grit/webapks_ui_resources.h",
       "webapks_ui_resources.pak",
     ]
     output_dir = "$root_gen_dir/chrome"
   }
 }