Implement API features for the Extension API feature system

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.
 
 {
   'targets': [
     {
       'target_name': 'common',
       'type': 'static_library',
       'variables': {
@@ skipping 205 matching lines @@
         'common/extensions/extension_manifest_constants.cc',
         'common/extensions/extension_manifest_constants.h',
         'common/extensions/extension_messages.cc',
         'common/extensions/extension_messages.h',
         'common/extensions/extension_process_policy.cc',
         'common/extensions/extension_process_policy.h',
         'common/extensions/extension_set.cc',
         'common/extensions/extension_set.h',
         'common/extensions/feature_switch.cc',
         'common/extensions/feature_switch.h',
+        'common/extensions/features/api_feature.cc',
+        'common/extensions/features/api_feature.h',
         'common/extensions/features/base_feature_provider.cc',
         'common/extensions/features/base_feature_provider.h',
         'common/extensions/features/complex_feature.cc',
         'common/extensions/features/complex_feature.h',
         'common/extensions/features/feature.cc',
         'common/extensions/features/feature.h',
         'common/extensions/features/feature_provider.h',
         'common/extensions/features/manifest_feature.cc',
         'common/extensions/features/manifest_feature.h',
         'common/extensions/features/permission_feature.cc',
@@ skipping 492 matching lines @@
         'common/metrics/proto/user_action_event.proto',
       ],
       'variables': {
         'proto_in_dir': 'common/metrics/proto',
         'proto_out_dir': 'chrome/common/metrics/proto',
       },
       'includes': [ '../build/protoc.gypi' ],
     },
   ],
 }