ES6 symbols: Allow symbols as property names

src/factory.h

 // Copyright 2012 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 42 matching lines @@
   Handle<FixedDoubleArray> NewFixedDoubleArray(
       int size,
       PretenureFlag pretenure = NOT_TENURED);
 
   Handle<SeededNumberDictionary> NewSeededNumberDictionary(
       int at_least_space_for);
 
   Handle<UnseededNumberDictionary> NewUnseededNumberDictionary(
       int at_least_space_for);
 
-  Handle<StringDictionary> NewStringDictionary(int at_least_space_for);
+  Handle<NameDictionary> NewNameDictionary(int at_least_space_for);
 
   Handle<ObjectHashSet> NewObjectHashSet(int at_least_space_for);
 
   Handle<ObjectHashTable> NewObjectHashTable(int at_least_space_for);
 
   Handle<DescriptorArray> NewDescriptorArray(int number_of_descriptors,
                                              int slack = 0);
   Handle<DeoptimizationInputData> NewDeoptimizationInputData(
       int deopt_entry_count,
       PretenureFlag pretenure);
@@ skipping 447 matching lines @@
   // Update the map cache in the native context with (keys, map)
   Handle<MapCache> AddToMapCache(Handle<Context> context,
                                  Handle<FixedArray> keys,
                                  Handle<Map> map);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FACTORY_H_