[ios] Add session saving support to clean skeleton.

ios/chrome/browser/browser_state/browser_state_keyed_service_factories.mm

Index: ios/chrome/browser/browser_state/browser_state_keyed_service_factories.mm
diff --git a/ios/chrome/browser/browser_state/browser_state_keyed_service_factories.mm b/ios/chrome/browser/browser_state/browser_state_keyed_service_factories.mm
index a87f1b14b37099885681c03fd8d98b5bd454a387..5faf7b4d1a22b8f97f1e55a75efc9de31ef9b017 100644
--- a/ios/chrome/browser/browser_state/browser_state_keyed_service_factories.mm
+++ b/ios/chrome/browser/browser_state/browser_state_keyed_service_factories.mm
@@ -46,6 +46,7 @@
 #include "ios/chrome/browser/translate/translate_accept_languages_factory.h"
 #include "ios/chrome/browser/undo/bookmark_undo_service_factory.h"
 #include "ios/chrome/browser/web_data_service_factory.h"
+#include "ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_factory.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -86,6 +87,7 @@ void EnsureBrowserStateKeyedServiceFactoriesBuilt() {
   ios::WebDataServiceFactory::GetInstance();
   ios::WebHistoryServiceFactory::GetInstance();
   AuthenticationServiceFactory::GetInstance();
+  BrowserListSessionServiceFactory::GetInstance();
   DesktopPromotionSyncServiceFactory::GetInstance();
   IOSChromeGCMProfileServiceFactory::GetInstance();
   IOSChromeLargeIconCacheFactory::GetInstance();