Move session service and supervised users to buildflags.

build/config/BUILD.gn

Index: build/config/BUILD.gn
diff --git a/build/config/BUILD.gn b/build/config/BUILD.gn
index 78aa47ad1bdd06e8f3acb20750b186c9afff1c14..3b2ce6e90c53ee4a39f43c50ef65bbf0fbaa4b34 100644
--- a/build/config/BUILD.gn
+++ b/build/config/BUILD.gn
@@ -189,15 +189,9 @@ config("feature_flags") {
   if (enable_themes) {
     defines += [ "ENABLE_THEMES=1" ]
   }
-  if (enable_session_service) {
-    defines += [ "ENABLE_SESSION_SERVICE=1" ]
-  }
   if (enable_rlz) {
     defines += [ "ENABLE_RLZ" ]
   }
-  if (enable_supervised_users) {
-    defines += [ "ENABLE_SUPERVISED_USERS=1" ]
-  }
   if (enable_image_loader_extension) {
     defines += [ "IMAGE_LOADER_EXTENSION=1" ]
   }