Enable extension APIs for content scripts.

chrome/chrome_tests.gypi

 # Copyright (c) 2011 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' : {
     # Variables for js2gtest rules
     'gypv8sh': '../tools/gypv8sh.py',
     'js2gtest': 'test/base/js2gtest.js',
     'mock_js': 'third_party/mock4js/mock4js.js',
     'test_api_js': 'test/data/webui/test_api.js',
@@ skipping 1886 matching lines @@
         'common/extensions/extension_resource_unittest.cc',
         'common/extensions/extension_set_unittest.cc',
         'common/extensions/extension_test_util.h',
         'common/extensions/extension_test_util.cc',
         'common/extensions/extension_unittest.cc',
         'common/extensions/extension_unpacker_unittest.cc',
         'common/extensions/update_manifest_unittest.cc',
         'common/extensions/url_pattern_set_unittest.cc',
         'common/extensions/url_pattern_unittest.cc',
         'common/extensions/user_script_unittest.cc',
+        'common/extensions/api/extension_api_unittest.cc',
         'common/guid_unittest.cc',
         'common/important_file_writer_unittest.cc',
         'common/json_pref_store_unittest.cc',
         'common/json_schema_validator_unittest.cc',
         'common/json_schema_validator_unittest_base.cc',
         'common/json_schema_validator_unittest_base.h',
         'common/json_value_serializer_unittest.cc',
         'common/mac/cfbundle_blocker_unittest.mm',
         'common/mac/objc_method_swizzle_unittest.mm',
         'common/mac/objc_zombie_unittest.mm',
@@ skipping 2334 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],  # 'coverage!=0'
   ],  # 'conditions'
 }