Notify launcher page with onTransitionChanged event

chrome/common/extensions/api/schemas.gypi

 # 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.
 
 {
   'sources': [
     '<@(schema_files)',
   ],
   'variables': {
     'main_schema_files': [
@@ skipping 39 matching lines @@
       'gcm.json',
       'hangouts_private.idl',
       'history.json',
       'hotword_private.idl',
       'i18n.json',
       'identity.idl',
       'identity_private.idl',
       'idle.json',
       'image_writer_private.idl',
       'input_ime.json',
+      'launcher_page.idl',
       'location.idl',
       'manifest_types.json',
       'mdns.idl',
       'media_galleries.idl',
       'media_galleries_private.idl',
       'metrics_private.json',
       'networking_private.json',
       'notification_provider.idl',
       'notifications.idl',
       'omnibox.json',
@@ skipping 95 matching lines @@
         'schema_files': [
           '<@(webrtc_schema_files)',
         ],
       }],
     ],
     'cc_dir': 'chrome/common/extensions/api',
     'root_namespace': 'extensions::api::%(namespace)s',
     'impl_dir_': 'chrome/browser/extensions/api',
   },
 }