Make the "Tabs" item on about:sync non-yellow

sync/syncable/model_type.cc

Index: sync/syncable/model_type.cc
diff --git a/sync/syncable/model_type.cc b/sync/syncable/model_type.cc
index caf58edeb3e4d4c9dc80a38282cbefe3023685ea..0e2cb688d5829c9a1b958d7d55904571a4bc9d96 100644
--- a/sync/syncable/model_type.cc
+++ b/sync/syncable/model_type.cc
@@ -1057,6 +1057,10 @@ bool IsRealDataType(ModelType model_type) {
   return model_type >= FIRST_REAL_MODEL_TYPE && model_type < MODEL_TYPE_COUNT;
 }
 
+bool IsProxyType(ModelType model_type) {
+  return model_type >= FIRST_PROXY_TYPE && model_type <= LAST_PROXY_TYPE;
+}
+
 bool IsActOnceDataType(ModelType model_type) {
   return model_type == HISTORY_DELETE_DIRECTIVES;
 }