Move session service and supervised users to buildflags.

chrome/browser/sessions/chrome_tab_restore_service_client.cc

Index: chrome/browser/sessions/chrome_tab_restore_service_client.cc
diff --git a/chrome/browser/sessions/chrome_tab_restore_service_client.cc b/chrome/browser/sessions/chrome_tab_restore_service_client.cc
index b20a44cca1d6e9ea5f15b7f216e26de8e3e52cd4..9ea44a2e4fa1c5976be78d4c8fedb4dbe8fb1222 100644
--- a/chrome/browser/sessions/chrome_tab_restore_service_client.cc
+++ b/chrome/browser/sessions/chrome_tab_restore_service_client.cc
@@ -121,7 +121,7 @@ GURL ChromeTabRestoreServiceClient::GetNewTabURL() {
 }
 
 bool ChromeTabRestoreServiceClient::HasLastSession() {
-#if defined(ENABLE_SESSION_SERVICE)
+#if BUILDFLAG(ENABLE_SESSION_SERVICE)
   SessionService* session_service =
       SessionServiceFactory::GetForProfile(profile_);
   Profile::ExitType exit_type = profile_->GetLastSessionExitType();
@@ -141,7 +141,7 @@ void ChromeTabRestoreServiceClient::GetLastSession(
     const sessions::GetLastSessionCallback& callback,
     base::CancelableTaskTracker* tracker) {
   DCHECK(HasLastSession());
-#if defined(ENABLE_SESSION_SERVICE)
+#if BUILDFLAG(ENABLE_SESSION_SERVICE)
   SessionServiceFactory::GetForProfile(profile_)
       ->GetLastSession(callback, tracker);
 #endif