Add more components to the GN build.

components/google.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/google/core/browser
       'target_name': 'google_core_browser',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
         '../net/net.gyp:net',
         '../ui/base/ui_base.gyp:ui_base',
         '../url/url.gyp:url_lib',
         'components_strings.gyp:components_strings',
         'keyed_service_core',
         'infobars_core',
         'url_fixer',
       ],
       'include_dirs': [
         '..',
       ],
       'sources': [
+        # Note: sources duplicated in GN build.
         'google/core/browser/google_pref_names.cc',
         'google/core/browser/google_pref_names.h',
         'google/core/browser/google_search_metrics.cc',
         'google/core/browser/google_search_metrics.h',
         'google/core/browser/google_switches.cc',
         'google/core/browser/google_switches.h',
         'google/core/browser/google_url_tracker.cc',
         'google/core/browser/google_url_tracker.h',
         'google/core/browser/google_url_tracker_client.cc',
         'google/core/browser/google_url_tracker_client.h',
         'google/core/browser/google_url_tracker_infobar_delegate.cc',
         'google/core/browser/google_url_tracker_infobar_delegate.h',
         'google/core/browser/google_url_tracker_map_entry.cc',
         'google/core/browser/google_url_tracker_map_entry.h',
         'google/core/browser/google_url_tracker_navigation_helper.cc',
         'google/core/browser/google_url_tracker_navigation_helper.h',
         'google/core/browser/google_util.cc',
         'google/core/browser/google_util.h',
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [4267, ],
     },
   ],
 }