Extend LargeIconService to fetch missing favicons from a Google server

ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc

Index: ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
diff --git a/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc b/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
index 5d01fb2c2fd665845f459159dc76b5b57852f3f8..25be550b59097a4acb80770192928c220104eb7f 100644
--- a/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
+++ b/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
@@ -9,6 +9,8 @@
 #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"
@@ -43,11 +45,16 @@ 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(