Add initial version of chrome://popular-sites-internals page

chrome/chrome_browser_ui.gypi

 # Copyright 2012 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': {
     # There are two sections of sources:
     # * "Platform"-based sources (OS, toolkit, etc.)
     # * Feature/directory-based sources (e.g., history, printing)
 
@@ skipping 507 matching lines @@
     'chrome_browser_ui_android_sources': [
       'browser/ui/android/autofill/credit_card_scanner_view_android.cc',
       'browser/ui/android/autofill/credit_card_scanner_view_android.h',
       'browser/ui/android/infobars/account_chooser_infobar.cc',
       'browser/ui/android/infobars/account_chooser_infobar.h',
       'browser/ui/android/infobars/generated_password_saved_infobar.cc',
       'browser/ui/android/infobars/generated_password_saved_infobar.h',
       'browser/ui/android/snackbars/auto_signin_snackbar_controller.cc',
       'browser/ui/android/snackbars/auto_signin_snackbar_controller.h',
       'browser/ui/screen_capture_notification_ui_stub.cc',
+      'browser/ui/webui/popular_sites_internals_message_handler.cc',
+      'browser/ui/webui/popular_sites_internals_message_handler.h',
+      'browser/ui/webui/popular_sites_internals_ui.cc',
+      'browser/ui/webui/popular_sites_internals_ui.h',
     ],
     # Cross-platform ash sources.
     'chrome_browser_ui_ash_sources': [
       'browser/ui/ash/app_list/app_list_controller_ash.cc',
       'browser/ui/ash/app_list/app_list_controller_ash.h',
       'browser/ui/ash/app_list/app_list_service_ash.cc',
       'browser/ui/ash/app_list/app_list_service_ash.h',
       'browser/ui/ash/app_list/app_sync_ui_state_watcher.cc',
       'browser/ui/ash/app_list/app_sync_ui_state_watcher.h',
       'browser/ui/ash/app_sync_ui_state.cc',
@@ skipping 2658 matching lines @@
           ],
           'sources': [
             '<@(chrome_browser_ui_non_mobile_sources)',
             '<@(chrome_browser_ui_omnibox_non_mobile_sources)',
           ],
         }],
       ],
     },
   ],
 }