Add an extension bubble explaining which extensions are in dev mode.

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 643 matching lines @@
         'browser/extensions/convert_user_script.h',
         'browser/extensions/convert_web_app.cc',
         'browser/extensions/convert_web_app.h',
         'browser/extensions/crx_installer.cc',
         'browser/extensions/crx_installer.h',
         'browser/extensions/crx_installer_error.h',
         'browser/extensions/data_deleter.cc',
         'browser/extensions/data_deleter.h',
         'browser/extensions/default_apps.cc',
         'browser/extensions/default_apps.h',
+        'browser/extensions/dev_mode_bubble_controller.cc',
+        'browser/extensions/dev_mode_bubble_controller.h',
         'browser/extensions/devtools_util.h',
         'browser/extensions/devtools_util.cc',
         'browser/extensions/error_console/error_console.cc',
         'browser/extensions/error_console/error_console.h',
         'browser/extensions/event_names.cc',
         'browser/extensions/event_names.h',
         'browser/extensions/event_router_forwarder.cc',
         'browser/extensions/event_router_forwarder.h',
         'browser/extensions/extension_action.cc',
         'browser/extensions/extension_action.h',
@@ skipping 32 matching lines @@
         'browser/extensions/extension_infobar_delegate.cc',
         'browser/extensions/extension_infobar_delegate.h',
         'browser/extensions/extension_install_prompt.cc',
         'browser/extensions/extension_install_prompt.h',
         'browser/extensions/extension_install_ui.cc',
         'browser/extensions/extension_install_ui.h',
         'browser/extensions/extension_installer.cc',
         'browser/extensions/extension_installer.h',
         'browser/extensions/extension_keybinding_registry.cc',
         'browser/extensions/extension_keybinding_registry.h',
+        'browser/extensions/extension_message_bubble_controller.cc',
+        'browser/extensions/extension_message_bubble_controller.h',
         'browser/extensions/policy_handlers.cc',
         'browser/extensions/policy_handlers.h',
         'browser/extensions/extension_pref_store.cc',
         'browser/extensions/extension_pref_store.h',
         'browser/extensions/extension_pref_value_map.cc',
         'browser/extensions/extension_pref_value_map.h',
         'browser/extensions/extension_pref_value_map_factory.cc',
         'browser/extensions/extension_pref_value_map_factory.h',
         'browser/extensions/extension_prefs.cc',
         'browser/extensions/extension_prefs.h',
@@ skipping 418 matching lines @@
             'browser/extensions/api/web_navigation/web_navigation_api_constants.cc',
             'browser/extensions/app_icon_loader_impl.cc',
             'browser/extensions/browser_extension_window_controller.cc',
             'browser/extensions/context_menu_matcher.cc',
             'browser/extensions/extension_context_menu_model.cc',
             'browser/extensions/extension_error_ui_default.cc',
             'browser/extensions/extension_error_ui_default.h',
             'browser/extensions/extension_function_util.cc',
             'browser/extensions/extension_infobar_delegate.cc',
             'browser/extensions/extension_install_ui.cc',
+            'browser/extensions/extension_list_bubble_controller.cc',
             'browser/extensions/extension_tab_util.cc',
             'browser/extensions/extension_uninstall_dialog.cc',
             'browser/extensions/suspicious_extension_bubble_controller.cc',
             'browser/extensions/suspicious_extension_bubble_controller.h',
             'browser/extensions/theme_installed_infobar_delegate.cc',
             'browser/extensions/webstore_startup_installer.cc',
             'browser/extensions/window_controller.cc',
             'browser/extensions/window_controller_list.cc',
           ],
         }],
@@ skipping 51 matching lines @@
           'variables': {
             'proto_in_dir': 'browser/chromeos/contacts',
             'proto_out_dir': 'chrome/browser/chromeos/contacts',
           },
           'includes': [ '../build/protoc.gypi' ]
         },
       ],
     },],  # 'chromeos=1'
   ],  # 'conditions'
 }