Add a user agent stylesheet for extension options pages

tools/gritsettings/resource_ids

 # Copyright (c) 2012 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.
 #
 # This file is used to assign starting resource ids for resources and strings
 # used by Chromium.  This is done to ensure that resource ids are unique
 # across all the grd files.  If you are adding a new grd file, please add
 # a new entry to this file.
 #
 # The first entry in the file, SRCDIR, is special: It is a relative path from
@@ skipping 161 matching lines @@
     "includes": [26400],
   },
   "extensions/extensions_resources.grd": {
     "includes": [26600],
   },
   "extensions/browser/resources/extensions_browser_resources.grd": {
     "structures": [26800],
   },
   "extensions/renderer/resources/extensions_renderer_resources.grd": {
     "includes": [26850],
+    "structures": [26950],
   },
   "extensions/extensions_strings.grd": {
     "messages": [27000],
   },
   "extensions/shell/app_shell_resources.grd": {
     "includes": [27400],
   },
   "chrome/browser/resources/memory_internals_resources.grd": {
     "includes": [27500],
   },
@@ skipping 28 matching lines @@
     "includes": [30250],
   },
   "components/resources/components_scaled_resources.grd": {
     "structures": [30350],
   },
   "third_party/WebKit/public/blink_resources.grd": {
     "includes": [30500],
   },
   # Resource ids starting at 31000 are reserved for projects built on Chromium.
 }