Parser & internalization fix: ensure no heap allocs during GetString(Handle<String>).

src/ast-value-factory.h

 // Copyright 2014 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 309 matching lines @@
   const AstValue* NewSymbol(const char* name);
   const AstValue* NewNumber(double number);
   const AstValue* NewSmi(int number);
   const AstValue* NewBoolean(bool b);
   const AstValue* NewStringList(ZoneList<const AstRawString*>* strings);
   const AstValue* NewNull();
   const AstValue* NewUndefined();
   const AstValue* NewTheHole();
 
  private:
-  const AstRawString* GetString(uint32_t hash, bool is_one_byte,
-                                Vector<const byte> literal_bytes);
+  AstRawString* GetString(uint32_t hash, bool is_one_byte,
+                          Vector<const byte> literal_bytes);
 
   // All strings are copied here, one after another (no NULLs inbetween).
   HashMap string_table_;
   // For keeping track of all AstValues and AstRawStrings we've created (so that
   // they can be internalized later).
   List<AstValue*> values_;
   List<AstString*> strings_;
   Zone* zone_;
   Isolate* isolate_;
 
@@ skipping 11 matching lines @@
 
 bool AstRawString::IsArguments(AstValueFactory* ast_value_factory) const {
   return ast_value_factory->arguments_string() == this;
 }
 } }  // namespace v8::internal
 
 #undef STRING_CONSTANTS
 #undef OTHER_CONSTANTS
 
 #endif  // V8_AST_VALUE_FACTORY_H_