Add an end-to-end test for sign-in profile apps installation

extensions/common/api/_behavior_features.json

 // 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.
 
 // This features file defines switches used to control Extension behaviour,
 // typically whitelist configuration.
 // See chrome/common/extensions/api/_features.md to understand this file, as
 // well as feature.h, simple_feature.h, and feature_provider.h.
 
 {
@@ skipping 20 matching lines @@
   "zoom_without_bubble": {
     "channel": "stable",
     "extension_types": "all",
     "whitelist": [
       "CBCC42ABED43A4B58FE3810E62AFFA010EB0349F"   // https://crbug.com/538252
     ]
   },
   "allow_usb_devices_permission_interface_class": {
     "channel": "stable",
     "extension_types": ["platform_app"],
-    "session_types": ["kiosk"] 
+    "session_types": ["kiosk"]
   },
   "signin_screen": [ {
     "blacklist": [
+      // https://crbug.com/626342
       "9E527CDA9D7C50844E8A5DB964A54A640AE48F98"   // Chrome remote desktop
     ],
     // Allow developers to test new features.
     "channel": "dev",
     "component_extensions_auto_granted": false,
     "extension_types": ["platform_app"],
     "location": "policy",
     "platforms": ["chromeos"]
   }, {
     // Strict restrictions for stable channel.
     // For now only whitelisted apps.
     "channel": "stable",
     "component_extensions_auto_granted": false,
     "extension_types": ["platform_app"],
     "location": "policy",
     "platforms": ["chromeos"],
     "whitelist": [
+      // https://crbug.com/626342
+      "85DA1AC24AF23CDA9F5A19858EB9C6E9E1BA57F6",  // Sign-in Screen Test App
       "EC3DE21E048B67319893889529354DFBFA96FD23",  // Smart Card Connector
       "6B748A5C005F21B7CBCF4170C2F883E435DEB511"   // CSSI Smart Card Middleware
     ]
   }, {
     // Explicitly whitelist extensions that should always be available
     // on a sign-in screen.
     "channel": "stable",
     "component_extensions_auto_granted": false,
     "platforms": ["chromeos"],
     "whitelist": [
+      // https://crbug.com/626342
       "E24F1786D842E91E74C27929B0B3715A4689A473",  // Gnubby component extension
       "6F9E349A0561C78A0D3F41496FE521C5151C7F71",  // Gnubby app
       "8EBDF73405D0B84CEABB8C7513C9B9FA9F1DC2CE",  // Genius app (help)
       "06BE211D5F014BAB34BC22D9DDA09C63A81D828E",  // Chrome OS XKB
       "3F50C3A83839D9C76334BCE81CDEC06174F266AF",  // Virtual Keyboard
       "2F47B526FA71F44816618C41EC55E5EE9543FDCC",  // Braille Keyboard
       "86672C8D7A04E24EFB244BF96FE518C4C4809F73",  // Speech synthesis
       "1CF709D51B2B96CF79D00447300BD3BFBE401D21",  // Mobile activation
       "D519188F86D9ACCEE0412007B227D9936EB9676B",  // Gaia auth extension
       "40FF1103292F40C34066E023B8BE8CAE18306EAE",  // Chromeos help
@@ skipping 12 matching lines @@
       "A3BC37E2148AC4E99BE4B16AF9D42DD1E592BBBE",  // http://crbug.com/335729
       "1C93BD3CF875F4A73C0B2A163BB8FBDA8B8B3D80",  // http://crbug.com/335729
       "307E96539209F95A1A8740C713E6998A73657D96",  // http://crbug.com/335729
       "4F25792AF1AA7483936DE29C07806F203C7170A0",  // http://crbug.com/407693
       "BD8781D757D830FC2E85470A1B6E8A718B7EE0D9",  // http://crbug.com/407693
       "4AC2B6C63C6480D150DFDA13E4A5956EB1D0DDBB",  // http://crbug.com/407693
       "81986D4F846CEDDDB962643FA501D1780DD441BB"   // http://crbug.com/407693
     ]
   }
 }