Add more extensions to the list.

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 base_feature_provider.h.
 
 {
@@ skipping 57 matching lines @@
     "whitelist": [
       "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"],
-    "location": "external_component",
     "whitelist": [
       "E24F1786D842E91E74C27929B0B3715A4689A473",  // Gnubby component extension
       "6F9E349A0561C78A0D3F41496FE521C5151C7F71",  // Gnubby app
       "8EBDF73405D0B84CEABB8C7513C9B9FA9F1DC2CE",  // Genius app (help)
-      "3F50C3A83839D9C76334BCE81CDEC06174F266AF"   // Virtual Keyboard
+      "06BE211D5F014BAB34BC22D9DDA09C63A81D828E",  // Chrome OS XKB
+      "3F50C3A83839D9C76334BCE81CDEC06174F266AF",  // Virtual Keyboard
+      "2F47B526FA71F44816618C41EC55E5EE9543FDCC",  // Braille Keyboard
+      "86672C8D7A04E24EFB244BF96FE518C4C4809F73",  // Speech synthesis
+      "1CF709D51B2B96CF79D00447300BD3BFBE401D21",  // Mobile activation
+      "D519188F86D9ACCEE0412007B227D9936EB9676B",  // Gaia auth extension
+      "40FF1103292F40C34066E023B8BE8CAE18306EAE",  // Chromeos help
+      "3C654B3B6682CA194E75AD044CEDE927675DDEE8",  // Easy unlock
+      "2FCBCE08B34CCA1728A85F1EFBD9A34DD2558B2E"   // ChromeVox
     ]
   }
   ]
 }