Attempt at work-around for http://crbug.com/16276 by explicitly checking...

src/objects.cc

 // Copyright 2006-2009 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 1614 matching lines @@
   Handle<JSFunction> fun(JSFunction::cast(setter));
   Handle<JSObject> self(this);
   bool has_pending_exception;
   Object** argv[] = { value_handle.location() };
   Execution::Call(fun, self, 1, argv, &has_pending_exception);
   // Check for pending exception and return the result.
   if (has_pending_exception) return Failure::Exception();
   return *value_handle;
 }
 
+
 void JSObject::LookupCallbackSetterInPrototypes(String* name,
                                                 LookupResult* result) {
   for (Object* pt = GetPrototype();
        pt != Heap::null_value();
        pt = pt->GetPrototype()) {
     JSObject::cast(pt)->LocalLookupRealNamedProperty(name, result);
     if (result->IsValid()) {
       if (!result->IsTransitionType() && result->IsReadOnly()) {
         result->NotFound();
         return;
       }
       if (result->type() == CALLBACKS) {
         return;
       }
     }
   }
   result->NotFound();
 }
 
 
 Object* JSObject::LookupCallbackSetterInPrototypes(uint32_t index) {
   for (Object* pt = GetPrototype();
        pt != Heap::null_value();
        pt = pt->GetPrototype()) {
     if (JSObject::cast(pt)->HasFastElements()) continue;
     NumberDictionary* dictionary = JSObject::cast(pt)->element_dictionary();
     int entry = dictionary->FindEntry(index);
-    if (entry != StringDictionary::kNotFound) {
+    if (entry != NumberDictionary::kNotFound) {
       Object* element = dictionary->ValueAt(entry);
       PropertyDetails details = dictionary->DetailsAt(entry);
       if (details.type() == CALLBACKS) {
         // Only accessors allowed as elements.
         return FixedArray::cast(element)->get(kSetterIndex);
       }
     }
   }
   return Heap::undefined_value();
 }
@@ skipping 6061 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single beak point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 
 } }  // namespace v8::internal