Add components and CLD to GN build.

components/captive_portal.gypi

 # Copyright 2014 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': [
     {
+      # GN version: //components/captive_portal
       'target_name': 'captive_portal',
       'type': '<(component)',
       'dependencies': [
         '../base/base.gyp:base',
         '../net/net.gyp:net',
         '../url/url.gyp:url_lib',
       ],
       'include_dirs': [
         '..',
       ],
       'defines': [
         'CAPTIVE_PORTAL_IMPLEMENTATION',
       ],
       'sources': [
+        # Note: sources list duplicated in GN build.
         'captive_portal/captive_portal_detector.cc',
         'captive_portal/captive_portal_detector.h',
         'captive_portal/captive_portal_types.cc',
         'captive_portal/captive_portal_types.h',
         'captive_portal/captive_portal_export.h',
       ],
     },
     {
+      # GN version: //components/captive_portal:test_support
       'target_name': 'captive_portal_test_support',
       'type': 'static_library',
       'dependencies': [
         'captive_portal',
         '../base/base.gyp:base',
         '../net/net.gyp:net',
         '../url/url.gyp:url_lib',
       ],
       'sources': [
+        # Note: sources list duplicated in GN build.
         'captive_portal/captive_portal_testing_utils.cc',
         'captive_portal/captive_portal_testing_utils.h',
       ],
     },
   ],
 }