ES6 symbols: Allow symbols as property names

src/v8globals.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 107 matching lines @@
 class DebugInfo;
 class Descriptor;
 class DescriptorArray;
 class TransitionArray;
 class ExternalReference;
 class FixedArray;
 class FunctionTemplateInfo;
 class MemoryChunk;
 class SeededNumberDictionary;
 class UnseededNumberDictionary;
-class StringDictionary;
+class NameDictionary;
 template <typename T> class Handle;
 class Heap;
 class HeapObject;
 class IC;
 class InterceptorInfo;
+class JSReceiver;
 class JSArray;
 class JSFunction;
 class JSObject;
 class LargeObjectSpace;
 class LookupResult;
 class MacroAssembler;
 class Map;
 class MapSpace;
 class MarkCompactCollector;
 class NewSpace;
 class Object;
 class MaybeObject;
 class OldSpace;
 class Foreign;
 class Scope;
 class ScopeInfo;
 class Script;
 class Smi;
 template <typename Config, class Allocator = FreeStoreAllocationPolicy>
     class SplayTree;
 class String;
+class Name;
 class Struct;
 class Variable;
 class RelocInfo;
 class Deserializer;
 class MessageLocation;
 class ObjectGroup;
 class TickSample;
 class VirtualMemory;
 class Mutex;
 
@@ skipping 402 matching lines @@
 
 enum ClearExceptionFlag {
   KEEP_EXCEPTION,
   CLEAR_EXCEPTION
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8GLOBALS_H_