[Icons NTP] Enable Large Icon URL storage and image fetching (Touch Icons only), behind flag.

chrome/browser/favicon/favicon_tab_helper.h

 // Copyright (c) 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.
 
 #ifndef CHROME_BROWSER_FAVICON_FAVICON_TAB_HELPER_H_
 #define CHROME_BROWSER_FAVICON_FAVICON_TAB_HELPER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 118 matching lines @@
 
   // Bypass cache when downloading favicons for this page URL.
   GURL bypass_cache_page_url_;
 
   scoped_ptr<FaviconHandler> favicon_handler_;
 
   // Handles downloading touchicons. It is NULL if
   // browser_defaults::kEnableTouchIcon is false.
   scoped_ptr<FaviconHandler> touch_icon_handler_;
 
+  scoped_ptr<FaviconHandler> large_icon_handler_;
+
   ObserverList<FaviconTabHelperObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(FaviconTabHelper);
 };
 
 #endif  // CHROME_BROWSER_FAVICON_FAVICON_TAB_HELPER_H_