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

src/isolate.cc

 // Copyright 2012 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/isolate.h"
 
 #include <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
@@ skipping 295 matching lines @@
 static bool IsVisibleInStackTrace(JSFunction* fun,
                                   Object* caller,
                                   Object* receiver,
                                   bool* seen_caller) {
   if ((fun == caller) && !(*seen_caller)) {
     *seen_caller = true;
     return false;
   }
   // Skip all frames until we've seen the caller.
   if (!(*seen_caller)) return false;
-  // Also, skip non-visible built-in functions and any call with the builtins
-  // object as receiver, so as to not reveal either the builtins object or
-  // an internal function.
+  // Functions defined in native scripts are not visible unless directly
+  // exposed, in which case the native flag is set.
   // The --builtins-in-stack-traces command line flag allows including
   // internal call sites in the stack trace for debugging purposes.
   if (!FLAG_builtins_in_stack_traces) {
     if (receiver->IsJSBuiltinsObject()) return false;
-    if (fun->IsBuiltin()) {
-      return fun->shared()->native();
-    } else if (!fun->IsSubjectToDebugging()) {
-      return false;
-    }
+    if (fun->IsBuiltin()) return fun->shared()->native();
   }
   return true;
 }
 
 
 Handle<Object> Isolate::CaptureSimpleStackTrace(Handle<JSObject> error_object,
                                                 Handle<Object> caller) {
   // Get stack trace limit.
   Handle<JSObject> error = error_function();
   Handle<String> stackTraceLimit =
@@ skipping 2477 matching lines @@
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8