Revert of ES6: Make function name configurable

src/accessors.cc

Index: src/accessors.cc
diff --git a/src/accessors.cc b/src/accessors.cc
index 51fdee67f28e5b0cd0ca0070842e5124de7fb2a1..052108a9b065feba47aa9ae907d55a9f33d092ab 100644
--- a/src/accessors.cc
+++ b/src/accessors.cc
@@ -1131,44 +1131,12 @@
 }
 
 
-MUST_USE_RESULT static MaybeHandle<Object> SetFunctionName(
-    Isolate* isolate, Handle<JSFunction> function, Handle<Object> value) {
-  Handle<Object> old_value;
-  bool is_observed = function->map()->is_observed();
-  if (is_observed) {
-    old_value = handle(function->shared()->name(), isolate);
-  }
-
-  Handle<Name> name = isolate->factory()->name_string();
-  LookupIterator it(function, name);
-  CHECK_EQ(LookupIterator::ACCESSOR, it.state());
-  DCHECK(it.HolderIsReceiverOrHiddenPrototype());
-  it.ReconfigureDataProperty(value, it.property_details().attributes());
-  value = it.WriteDataValue(value);
-
-  if (is_observed && !old_value->SameValue(*value)) {
-    return JSObject::EnqueueChangeRecord(function, "update", name, old_value);
-  }
-
-  return value;
-}
-
-
 void Accessors::FunctionNameSetter(
     v8::Local<v8::Name> name,
     v8::Local<v8::Value> val,
     const v8::PropertyCallbackInfo<void>& info) {
-  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
-  HandleScope scope(isolate);
-  Handle<Object> value = Utils::OpenHandle(*val);
-
-  if (SetPropertyOnInstanceIfInherited(isolate, info, name, value)) return;
-
-  Handle<JSFunction> object =
-      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
-  if (SetFunctionName(isolate, object, value).is_null()) {
-    isolate->OptionalRescheduleException(false);
-  }
+  // Function name is non writable, non configurable.
+  UNREACHABLE();
 }