Do not break in native code (including non-builtin debugger code).

src/objects-inl.h

 // 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 5400 matching lines @@
     code()->set_optimizable(true);
   }
 }
 
 
 bool JSFunction::IsBuiltin() {
   return context()->global_object()->IsJSBuiltinsObject();
 }
 
 
+bool JSFunction::IsNative() {
+  Object* script = shared()->script();
+  bool native = script->IsScript() &&
+                Script::cast(script)->type()->value() == Script::TYPE_NATIVE;
+  ASSERT(!IsBuiltin() || native);  // All builtins are also native.
+  return native;
+}
+
+
 bool JSFunction::NeedsArgumentsAdaption() {
   return shared()->formal_parameter_count() !=
       SharedFunctionInfo::kDontAdaptArgumentsSentinel;
 }
 
 
 bool JSFunction::IsOptimized() {
   return code()->kind() == Code::OPTIMIZED_FUNCTION;
 }
 
@@ skipping 1414 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_