JSON.parse improvement. Call "LookupSymbol" rather than "NewString"...

src/parser.h

 // 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 796 matching lines @@
   // of JSON values.
   // A JSON array doesn't allow leaving out values from the sequence, nor does
   // it allow a terminal comma, like a JavaScript array does.
   Handle<Object> ParseJsonArray();
 
   // Mark that a parsing error has happened at the current token, and
   // return a null handle. Primarily for readability.
   Handle<Object> ReportUnexpectedToken() { return Handle<Object>::null(); }
   // Converts the currently parsed literal to a JavaScript String.
   Handle<String> GetString();
+  // Converts the currently parsed literal to a JavaScript Symbol String.
+  Handle<String> GetSymbol();
 
   Isolate* isolate_;
   JsonScanner scanner_;
   bool stack_overflow_;
 };
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_