Show notification instead of opening app launcher after extension installation

extensions/common/api/app_runtime.idl

 // 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.
 
 // Use the <code>chrome.app.runtime</code> API to manage the app lifecycle.
 // The app runtime manages app installation, controls the event page, and can
 // shut down the app at anytime.
 namespace app.runtime {
 
   [inline_doc] dictionary LaunchItem {
@@ skipping 16 matching lines @@
     url_handler,
     system_tray,
     about_page,
     keyboard,
     extensions_page,
     management_api,
     ephemeral_app,
     background,
     kiosk,
     chrome_internal,
-    test
+    test,
+    installed_notification
   };
 
   // Optional data for the launch. Either <code>items</code>, or
   // the pair (<code>url, referrerUrl</code>) can be present for any given
   // launch.
   [inline_doc] dictionary LaunchData {
     // The ID of the file or URL handler that the app is being invoked with.
     // Handler IDs are the top-level keys in the <code>file_handlers</code>
     // and/or <code>url_handlers</code> dictionaries in the manifest.
     DOMString? id;
@@ skipping 54 matching lines @@
 
     // Fired at Chrome startup to apps that were running when Chrome last shut
     // down, or when apps have been requested to restart from their previous
     // state for other reasons (e.g. when the user revokes access to an app's
     // retained files the runtime will restart the app). In these situations if
     // apps do not have an <code>onRestarted</code> handler they will be sent
     // an <code>onLaunched </code> event instead.
     static void onRestarted();
   };
 };