Avoid duplication of a hidden & inherited prototype's properties.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 8d84fdace2562f4f6f834940706f298bfdf481a5..89d49fe78cdf73c6da7d600c5ebb66ea37d313a4 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -5726,6 +5726,22 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetPropertyNamesFast) {
 }
 
 
+// Returns true if inherited accessors have been copied down
+// to obj from proto's function template.
+static bool IsInheritedApiFunctionOf(JSObject *obj, Object *proto) {
+  Object *constructor = HeapObject::cast(proto)->map()->constructor();
+  if (!constructor->IsJSFunction()) {

[jochen (gone - plz use gerrit), 2013/12/17 15:00:53]

nit. v8 style is if (...) return false; (in one line). if it doesn't fit in one
line, but the body is just one line, no need for { }

+    return false;
+  }
+  JSFunction *constructor_fun = JSFunction::cast(constructor);
+  if (!constructor_fun->shared()->IsApiFunction()) {
+    return false;
+  }
+  return constructor_fun->shared()->

[jochen (gone - plz use gerrit), 2013/12/17 15:00:53]

nit the -> should go on the next line

+      get_api_func_data()->IsTemplateFor(obj);
+}
+
+
 // Find the length of the prototype chain that is to to handled as one. If a
 // prototype object is hidden it is to be viewed as part of the the object it
 // is prototype for.
@@ -5733,7 +5749,8 @@ static int LocalPrototypeChainLength(JSObject* obj) {
   int count = 1;
   Object* proto = obj->GetPrototype();
   while (proto->IsJSObject() &&
-         JSObject::cast(proto)->map()->is_hidden_prototype()) {
+         JSObject::cast(proto)->map()->is_hidden_prototype() &&
+         !IsInheritedApiFunctionOf(obj, proto)) {
     count++;
     proto = JSObject::cast(proto)->GetPrototype();
   }