Convert the re2 GYP targets to be generated by GN.

extensions/extensions.gyp

 # Copyright 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': {
     'chromium_code': 1,
   },
   'targets': [
     {
       'target_name': 'extensions_common',
       'type': 'static_library',
       'dependencies': [
         # TODO(benwells): figure out what to do with the api target and
         # api resources compiled into the chrome resource bundle.
         # http://crbug.com/162530
         '../chrome/chrome_resources.gyp:chrome_resources',
         '../chrome/common/extensions/api/api.gyp:api',
         '../content/content.gyp:content_common',
-        '../third_party/re2/re2.gyp:re2',
+        '../out/gn_gyp/third_party/re2/re2.gyp:re2',
       ],
       'include_dirs': [
         '..',
         '<(INTERMEDIATE_DIR)',
       ],
       'sources': [
         'common/crx_file.cc',
         'common/crx_file.h',
         'common/csp_validator.cc',
         'common/csp_validator.h',
@@ skipping 176 matching lines @@
         'browser/quota_service.h',
         'browser/update_observer.h',
         'browser/view_type_utils.cc',
         'browser/view_type_utils.h',
       ],
       # Disable c4267 warnings until we fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
   ]
 }