Do not use js builtins object to determine whether a function is a builtin.

src/runtime/runtime-function.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/compiler.h"
 #include "src/cpu-profiler.h"
@@ skipping 174 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_FunctionIsAPIFunction) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, f, 0);
   return isolate->heap()->ToBoolean(f->shared()->IsApiFunction());
 }
 
 
-RUNTIME_FUNCTION(Runtime_FunctionIsBuiltin) {
+RUNTIME_FUNCTION(Runtime_FunctionHidesSource) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
 
-  CONVERT_ARG_CHECKED(JSFunction, f, 0);
-  return isolate->heap()->ToBoolean(f->IsBuiltin());
+  SharedFunctionInfo* shared = f->shared();
+  bool hide_source = !shared->script()->IsScript() ||
+                     Script::cast(shared->script())->hide_source();
+  return isolate->heap()->ToBoolean(hide_source);
 }
 
 
 RUNTIME_FUNCTION(Runtime_SetCode) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
 
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, target, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, source, 1);
 
@@ skipping 434 matching lines @@
 
 
 RUNTIME_FUNCTION(Runtime_ThrowStrongModeTooFewArguments) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 0);
   THROW_NEW_ERROR_RETURN_FAILURE(isolate,
                                  NewTypeError(MessageTemplate::kStrongArity));
 }
 }  // namespace internal
 }  // namespace v8