Extend LargeIconService to fetch missing favicons from a Google server

components/favicon/core/features.cc

+// Copyright 2017 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.
+
+#include "components/favicon/core/features.h"
+
+namespace favicon {
+
+const base::Feature kFaviconFetchLargeIconFromGoogleServer1{
+    "FaviconFetchLargeIconFromGoogleServer1", base::FEATURE_ENABLED_BY_DEFAULT};
+const base::Feature kFaviconFetchLargeIconFromGoogleServer2{
+    "FaviconFetchLargeIconFromGoogleServer2",
+    base::FEATURE_DISABLED_BY_DEFAULT};
+
+}  // namespace favicon