Fix assert in Runtime_SetIsObserved.

src/objects.cc

 // Copyright 2013 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 5634 matching lines @@
     dictionary->set_requires_slow_elements();
     // Freeze all elements in the dictionary
     FreezeDictionary(dictionary);
   }
 
   return object;
 }
 
 
 void JSObject::SetObserved(Handle<JSObject> object) {
+  ASSERT(!object->map()->is_observed());
   Isolate* isolate = object->GetIsolate();
 
-  if (object->map()->is_observed())
-    return;
-
   LookupResult result(isolate);
   object->map()->LookupTransition(*object,
                                   isolate->heap()->observed_symbol(),
                                   &result);
 
   Handle<Map> new_map;
   if (result.IsTransition()) {
     new_map = handle(result.GetTransitionTarget());
     ASSERT(new_map->is_observed());
   } else if (object->map()->CanHaveMoreTransitions()) {
@@ skipping 10822 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal