A MessageObject is a purely internal object to hold information about

src/factory.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 737 matching lines @@
   // allocate extra space for a literals array prefix containing the
   // context.
   if (number_of_literals > 0) {
     literals_array_size += JSFunction::kLiteralsPrefixSize;
   }
   shared->set_num_literals(literals_array_size);
   return shared;
 }
 
 
+Handle<JSMessageObject> Factory::NewJSMessageObject(
+    Handle<String> type,
+    Handle<JSArray> arguments,
+    int start_position,
+    int end_position,
+    Handle<Object> script,
+    Handle<Object> stack_trace,
+    Handle<Object> stack_frames) {
+  CALL_HEAP_FUNCTION(Heap::AllocateJSMessageObject(*type,
+                                                   *arguments,
+                                                   start_position,
+                                                   end_position,
+                                                   *script,
+                                                   *stack_trace,
+                                                   *stack_frames),
+                     JSMessageObject);
+}
+
 Handle<SharedFunctionInfo> Factory::NewSharedFunctionInfo(Handle<String> name) {
   CALL_HEAP_FUNCTION(Heap::AllocateSharedFunctionInfo(*name),
                      SharedFunctionInfo);
 }
 
 
 Handle<String> Factory::NumberToString(Handle<Object> number) {
   CALL_HEAP_FUNCTION(Heap::NumberToString(*number), String);
 }
 
@@ skipping 285 matching lines @@
     Execution::ConfigureInstance(instance,
                                  instance_template,
                                  pending_exception);
   } else {
     *pending_exception = false;
   }
 }
 
 
 } }  // namespace v8::internal