Add infrastructure to keep track of references to prototypes.

src/lookup.h

Index: src/lookup.h
diff --git a/src/lookup.h b/src/lookup.h
index a78bb5d91d658cd7d1e04c709d5c0fe9f731cf61..4108a49aad43dcb5dc31964660c5ca552d167540 100644
--- a/src/lookup.h
+++ b/src/lookup.h
@@ -175,7 +175,8 @@ class LookupIterator FINAL BASE_EMBEDDED {
   static Configuration ComputeConfiguration(
       Configuration configuration, Handle<Name> name) {
     if (name->IsOwn()) {
-      return static_cast<Configuration>(configuration & HIDDEN);
+      return static_cast<Configuration>(configuration &
+                                        HIDDEN_SKIP_INTERCEPTOR);
     } else {
       return configuration;
     }