Add a chrome://interstitials page.

chrome/chrome_browser_ui.gypi

 # Copyright 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.
 
 {
   'variables': {
     'chrome_browser_ui_non_ios_sources': [
       'browser/ui/accelerator_utils.h',
       'browser/ui/android/android_about_app_info.cc',
       'browser/ui/android/android_about_app_info.h',
@@ skipping 1040 matching lines @@
       'browser/ui/webui/flags_ui.cc',
       'browser/ui/webui/flags_ui.h',
       'browser/ui/webui/flash_ui.cc',
       'browser/ui/webui/flash_ui.h',
       'browser/ui/webui/gcm_internals_ui.cc',
       'browser/ui/webui/gcm_internals_ui.h',
       'browser/ui/webui/history_ui.cc',
       'browser/ui/webui/history_ui.h',
       'browser/ui/webui/instant_ui.cc',
       'browser/ui/webui/instant_ui.h',
+      'browser/ui/webui/interstitials/interstitial_ui.cc',
+      'browser/ui/webui/interstitials/interstitial_ui.h',
       'browser/ui/webui/invalidations_message_handler.cc',
       'browser/ui/webui/invalidations_message_handler.h',
       'browser/ui/webui/invalidations_ui.cc',
       'browser/ui/webui/invalidations_ui.h',
       'browser/ui/webui/memory_internals/memory_internals_handler.cc',
       'browser/ui/webui/memory_internals/memory_internals_handler.h',
       'browser/ui/webui/memory_internals/memory_internals_proxy.cc',
       'browser/ui/webui/memory_internals/memory_internals_proxy.h',
       'browser/ui/webui/memory_internals/memory_internals_ui.cc',
       'browser/ui/webui/memory_internals/memory_internals_ui.h',
@@ skipping 1889 matching lines @@
         }],
         ['OS!="android" and OS!="ios"', {
           'dependencies': [
             '../device/bluetooth/bluetooth.gyp:device_bluetooth',
           ],
         }],
       ],
     },
   ],
 }