Use NativesFlag to allow/disallow natives syntax during compilation.

src/compiler.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 511 matching lines @@
     }
 
     script->set_data(script_data.is_null() ? Heap::undefined_value()
                                            : *script_data);
 
     // Compile the function and add it to the cache.
     CompilationInfo info(script);
     info.MarkAsGlobal();
     info.SetExtension(extension);
     info.SetPreParseData(pre_data);
+    if (natives == NATIVES_CODE) info.MarkAsAllowingNativesSyntax();
     result = MakeFunctionInfo(&info);
     if (extension == NULL && !result.is_null()) {
       CompilationCache::PutScript(source, result);
     }
 
     // Get rid of the pre-parsing data (if necessary).
     if (input_pre_data == NULL && pre_data != NULL) {
       delete pre_data;
     }
   }
@@ skipping 256 matching lines @@
                               shared->DebugName()));
     }
   }
 
   GDBJIT(AddCode(name,
                  Handle<Script>(info->script()),
                  Handle<Code>(info->code())));
 }
 
 } }  // namespace v8::internal