Changed SetPropertyPostInterceptor to climb the prototype chain to

src/objects.cc

 // Copyright 2011 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 1620 matching lines @@
   }
   return AddSlowProperty(name, value, attributes);
 }
 
 
 MaybeObject* JSObject::SetPropertyPostInterceptor(
     String* name,
     Object* value,
     PropertyAttributes attributes,
     StrictModeFlag strict_mode) {
-  // Check local property, ignore interceptor.
+  // Check local and prototype properties, ignore interceptor.
   LookupResult result;
-  LocalLookupRealNamedProperty(name, &result);
+  LookupRealNamedProperty(name, &result);
   if (result.IsFound()) {
     // An existing property, a map transition or a null descriptor was
     // found.  Use set property to handle all these cases.
     return SetProperty(&result, name, value, attributes, strict_mode);
   }
   // Add a new real property.
   return AddProperty(name, value, attributes, strict_mode);
 }
 
 
@@ skipping 9899 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single break point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 
 } }  // namespace v8::internal