Add gn implementation for //components/history/ios/browser.

components/history.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/history/core/browser
       'target_name': 'history_core_browser',
       'type': 'static_library',
@@ skipping 225 matching lines @@
             'history/content/browser/history_database_helper.h',
             'history/content/browser/web_contents_top_sites_observer.cc',
             'history/content/browser/web_contents_top_sites_observer.h',
           ],
         }
       ],
     }],
     ['OS=="ios"', {
       'targets': [
         {
+          # GN version: //components/history/ios/browser
           'target_name': 'history_ios_browser',
           'type': 'static_library',
           'include_dirs': [
             '..',
           ],
           'dependencies': [
             '../base/base.gyp:base',
             '../ios/web/ios_web.gyp:ios_web',
             '../url/url.gyp:url_lib',
             'history_core_browser',
           ],
           'sources': [
             'history/ios/browser/history_database_helper.cc',
             'history/ios/browser/history_database_helper.h',
             'history/ios/browser/web_state_top_sites_observer.cc',
             'history/ios/browser/web_state_top_sites_observer.h',
           ],
         },
       ],
     }],
   ],
 }