Move session service and supervised users to buildflags.

chrome/browser/extensions/extension_sync_service.cc

Index: chrome/browser/extensions/extension_sync_service.cc
diff --git a/chrome/browser/extensions/extension_sync_service.cc b/chrome/browser/extensions/extension_sync_service.cc
index f191331b2e8f295ad5abc8c4b95f7ed2cbb393d7..4ca790b6f821048ec91bfe2c780a53cb649ed5d3 100644
--- a/chrome/browser/extensions/extension_sync_service.cc
+++ b/chrome/browser/extensions/extension_sync_service.cc
@@ -19,6 +19,7 @@
 #include "chrome/browser/sync/glue/sync_start_util.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/sync_helper.h"
+#include "chrome/common/features.h"
 #include "chrome/common/web_application_info.h"
 #include "components/sync/model/sync_change.h"
 #include "components/sync/model/sync_error_factory.h"
@@ -34,7 +35,7 @@
 #include "extensions/common/permissions/permission_message_provider.h"
 #include "extensions/common/permissions/permissions_data.h"
 
-#if defined(ENABLE_SUPERVISED_USERS)
+#if BUILDFLAG(ENABLE_SUPERVISED_USERS)
 #include "chrome/browser/supervised_user/supervised_user_service.h"
 #include "chrome/browser/supervised_user/supervised_user_service_factory.h"
 #endif
@@ -442,7 +443,7 @@ void ExtensionSyncService::ApplySyncData(
       else if (extension_sync_data.supports_disable_reasons())
         reenable_after_update = true;
 
-#if defined(ENABLE_SUPERVISED_USERS)
+#if BUILDFLAG(ENABLE_SUPERVISED_USERS)
       if (!has_all_permissions && (state == INSTALLED_NEWER) &&
           extensions::util::IsExtensionSupervised(extension, profile_)) {
         SupervisedUserServiceFactory::GetForProfile(profile_)