Add baked-in favicons for default popular sites on NTP

components/ntp_tiles/icon_cacher_impl.h

 // Copyright 2016 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.
 
 #ifndef COMPONENTS_NTP_TILES_ICON_CACHER_IMPL_H_
 #define COMPONENTS_NTP_TILES_ICON_CACHER_IMPL_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 34 matching lines @@
   void OnGetFaviconImageForPageURLFinished(
       PopularSites::Site site,
       const base::Callback<void(bool)>& done,
       const favicon_base::FaviconImageResult& result);
 
   void OnFaviconDownloaded(PopularSites::Site site,
                            const base::Callback<void(bool)>& done,
                            const std::string& id,
                            const gfx::Image& fetched_image);
 
+  bool ProvideDefaultIcon(const PopularSites::Site& site);
+  void SaveIconForSite(const PopularSites::Site& site, const gfx::Image image);
+
   base::CancelableTaskTracker tracker_;
   favicon::FaviconService* const favicon_service_;
   std::unique_ptr<image_fetcher::ImageFetcher> const image_fetcher_;
 
   DISALLOW_COPY_AND_ASSIGN(IconCacherImpl);
 };
 
 }  // namespace ntp_tiles
 
 #endif  // COMPONENTS_NTP_TILES_ICON_CACHER_IMPL_H_