Extend LargeIconService to fetch missing favicons from a Google server

ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc

 // Copyright 2015 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 "ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/favicon/core/large_icon_service.h"
+#include "components/image_fetcher/core/image_fetcher_impl.h"
+#include "components/image_fetcher/ios/ios_image_decoder_impl.h"
 #include "components/keyed_service/core/service_access_type.h"
 #include "components/keyed_service/ios/browser_state_dependency_manager.h"
 #include "ios/chrome/browser/browser_state/browser_state_otr_helper.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/favicon/favicon_service_factory.h"
 #include "ios/web/public/web_thread.h"
 
 // static
 favicon::LargeIconService* IOSChromeLargeIconServiceFactory::GetForBrowserState(
     ios::ChromeBrowserState* browser_state) {
@@ skipping 14 matching lines @@
   DependsOn(ios::FaviconServiceFactory::GetInstance());
 }
 
 IOSChromeLargeIconServiceFactory::~IOSChromeLargeIconServiceFactory() {}
 
 std::unique_ptr<KeyedService>
 IOSChromeLargeIconServiceFactory::BuildServiceInstanceFor(
     web::BrowserState* context) const {
   ios::ChromeBrowserState* browser_state =
       ios::ChromeBrowserState::FromBrowserState(context);
+  base::SequencedWorkerPool* sequenced_worker_pool =
+      web::WebThread::GetBlockingPool();
 
   return base::MakeUnique<favicon::LargeIconService>(
       ios::FaviconServiceFactory::GetForBrowserState(
           browser_state, ServiceAccessType::EXPLICIT_ACCESS),
-      web::WebThread::GetBlockingPool());
+      sequenced_worker_pool,
+      base::MakeUnique<image_fetcher::ImageFetcherImpl>(
+          image_fetcher::CreateIOSImageDecoder(sequenced_worker_pool),
+          browser_state->GetRequestContext()));
 }
 
 web::BrowserState* IOSChromeLargeIconServiceFactory::GetBrowserStateToUse(
     web::BrowserState* context) const {
   return GetBrowserStateOwnInstanceInIncognito(context);
 }
 
 bool IOSChromeLargeIconServiceFactory::ServiceIsNULLWhileTesting() const {
   return true;
 }