Declare providing extension capabilities in the manifest.

chrome/chrome_common.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.
 
 {
   'variables': {
     # File lists shared with GN build.
     'chrome_common_sources': [
       'common/all_messages.h',
       'common/attrition_experiments.h',
@@ skipping 190 matching lines @@
       'common/extensions/manifest_handlers/ui_overrides_handler.h',
       'common/extensions/permissions/chrome_api_permissions.cc',
       'common/extensions/permissions/chrome_api_permissions.h',
       'common/extensions/permissions/chrome_permission_message_provider.cc',
       'common/extensions/permissions/chrome_permission_message_provider.h',
       'common/extensions/permissions/chrome_permission_message_rules.cc',
       'common/extensions/permissions/chrome_permission_message_rules.h',
       'common/extensions/sync_helper.cc',
       'common/extensions/sync_helper.h',
     ],
+    'chrome_common_extensions_chromeos_sources': [
+      'common/extensions/api/file_system_provider/file_system_provider_handler.cc',
+      'common/extensions/api/file_system_provider/file_system_provider_handler.h',
+    ],
     'chrome_common_full_safe_browsing_sources': [
       'common/safe_browsing/binary_feature_extractor.cc',
       'common/safe_browsing/binary_feature_extractor.h',
       'common/safe_browsing/binary_feature_extractor_posix.cc',
       'common/safe_browsing/binary_feature_extractor_win.cc',
       'common/safe_browsing/download_protection_util.cc',
       'common/safe_browsing/download_protection_util.h',
       'common/safe_browsing/ipc_protobuf_message_macros.h',
       'common/safe_browsing/ipc_protobuf_message_null_macros.h',
       'common/safe_browsing/pe_image_reader_win.cc',
@@ skipping 140 matching lines @@
             '<(DEPTH)/extensions/common/api/api.gyp:extensions_api',
             '<(DEPTH)/extensions/extensions.gyp:extensions_common',
             '<(DEPTH)/extensions/extensions_resources.gyp:extensions_resources',
             '<(DEPTH)/extensions/extensions_strings.gyp:extensions_strings',
             '<(DEPTH)/media/cast/cast.gyp:cast_net',
           ],
           'export_dependent_settings': [
             '<(DEPTH)/chrome/common/extensions/api/api.gyp:chrome_api',
           ],
         }],
+        ['enable_extensions==1 and chromeos==1', {
+          'sources': [ '<@(chrome_common_extensions_chromeos_sources)' ],
+        }],
         ['OS=="win" or OS=="mac"', {
           'sources': [ '<@(chrome_common_win_mac_sources)' ],
         }],
         ['(OS=="win" or OS=="mac" or chromeos==1) and use_openssl==1', {
           'sources': [ '<@(chrome_common_networking_private_sources_openssl)' ],
           'dependencies': [
             '../third_party/boringssl/boringssl.gyp:boringssl',
           ],
         }],
         ['(OS=="win" or OS=="mac" or chromeos==1) and use_openssl!=1', {
@@ skipping 301 matching lines @@
         'common/safe_browsing/csd.proto'
       ],
       'variables': {
         'proto_in_dir': 'common/safe_browsing',
         'proto_out_dir': 'chrome/common/safe_browsing',
       },
       'includes': [ '../build/protoc.gypi' ],
     },
   ],
 }