Add stubs for brailleDisplayPrivate extension API.

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 116 matching lines @@
         'browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.cc',
         'browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api.h',
         'browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api_constants.cc',
         'browser/extensions/api/bookmark_manager_private/bookmark_manager_private_api_constants.h',
         'browser/extensions/api/bookmarks/bookmark_api_constants.cc',
         'browser/extensions/api/bookmarks/bookmark_api_constants.h',
         'browser/extensions/api/bookmarks/bookmark_api_helpers.cc',
         'browser/extensions/api/bookmarks/bookmark_api_helpers.h',
         'browser/extensions/api/bookmarks/bookmarks_api.cc',
         'browser/extensions/api/bookmarks/bookmarks_api.h',
+        'browser/extensions/api/braille_display_private/braille_display_private_api.h',
+        'browser/extensions/api/braille_display_private/braille_display_private_api.cc',
         'browser/extensions/api/browsing_data/browsing_data_api.cc',
         'browser/extensions/api/browsing_data/browsing_data_api.h',
         'browser/extensions/api/cloud_print_private/cloud_print_private_api.cc',
         'browser/extensions/api/cloud_print_private/cloud_print_private_api.h',
         'browser/extensions/api/command_line_private/command_line_private_api.cc',
         'browser/extensions/api/command_line_private/command_line_private_api.h',
         'browser/extensions/api/commands/command_service.cc',
         'browser/extensions/api/commands/command_service.h',
         'browser/extensions/api/content_settings/content_settings_api.cc',
         'browser/extensions/api/content_settings/content_settings_api.h',
@@ skipping 892 matching lines @@
           'variables': {
             'proto_in_dir': 'browser/chromeos/contacts',
             'proto_out_dir': 'chrome/browser/chromeos/contacts',
           },
           'includes': [ '../build/protoc.gypi' ]
         },
       ],
     },],  # 'chromeos=1'
   ],  # 'conditions'
 }