Settings Overides -- warn user when extensions override their NTP.

chrome/chrome_browser_extensions.gypi

 # Copyright (c) 2013 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.
 
 {
   'targets': [
     {
       'target_name': 'browser_extensions',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 806 matching lines @@
         'browser/extensions/install_verifier.h',
         'browser/extensions/launch_util.cc',
         'browser/extensions/launch_util.h',
         'browser/extensions/location_bar_controller.h',
         'browser/extensions/menu_manager.cc',
         'browser/extensions/menu_manager.h',
         'browser/extensions/menu_manager_factory.cc',
         'browser/extensions/menu_manager_factory.h',
         'browser/extensions/navigation_observer.cc',
         'browser/extensions/navigation_observer.h',
+        'browser/extensions/ntp_controlled_bubble_controller.cc',
+        'browser/extensions/ntp_controlled_bubble_controller.h',
         'browser/extensions/pack_extension_job.cc',
         'browser/extensions/pack_extension_job.h',
         'browser/extensions/page_action_controller.cc',
         'browser/extensions/page_action_controller.h',
         'browser/extensions/pending_enables.cc',
         'browser/extensions/pending_enables.h',
         'browser/extensions/pending_extension_info.cc',
         'browser/extensions/pending_extension_info.h',
         'browser/extensions/pending_extension_manager.cc',
         'browser/extensions/pending_extension_manager.h',
@@ skipping 367 matching lines @@
       'type': 'static_library',
       'sources': [ 'browser/extensions/api/cast_channel/cast_channel.proto' ],
       'variables': {
           'proto_in_dir': 'browser/extensions/api/cast_channel',
           'proto_out_dir': 'chrome/browser/extensions/api/cast_channel',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],  # 'conditions'
 }