Move prototype metadata from internal properties to prototype maps

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 5dac6a1ada3454980e348caf6a76b8268d51ee0d..ce7f758cb52f67a742ae37fb95d5db2fed3c274c 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -51,6 +51,15 @@ Handle<Box> Factory::NewBox(Handle<Object> value) {
 }
 
 
+Handle<PrototypeInfo> Factory::NewPrototypeInfo() {
+  Handle<PrototypeInfo> result =
+      Handle<PrototypeInfo>::cast(NewStruct(PROTOTYPE_INFO_TYPE));
+  result->set_prototype_users(WeakFixedArray::Empty());
+  result->set_validity_cell(Smi::FromInt(0));
+  return result;
+}
+
+
 Handle<Oddball> Factory::NewOddball(Handle<Map> map,
                                     const char* to_string,
                                     Handle<Object> to_number,