Don't use vm heap for symbols yet, we need to change the snapshot writer to not mark object header …

vm/symbols.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_SYMBOLS_H_
 #define VM_SYMBOLS_H_
 
 #include "vm/object.h"
 
 namespace dart {
@@ skipping 52 matching lines @@
 #define DEFINE_SYMBOL_INDEX(symbol, literal)                                   \
   k##symbol,
 PREDEFINED_SYMBOLS_LIST(DEFINE_SYMBOL_INDEX)
 #undef DEFINE_SYMBOL_INDEX
 
     kMaxPredefined,
   };
 
   // Access methods for symbols stored in the vm isolate.
 #define DEFINE_SYMBOL_ACCESSOR(symbol, literal)                                \
-  static RawString* symbol() { return predefined_[k##symbol]; }
+  static RawString* symbol() { return Symbols::New(literal); }
 PREDEFINED_SYMBOLS_LIST(DEFINE_SYMBOL_ACCESSOR)
 #undef DEFINE_SYMBOL_ACCESSOR
 
   // Initialize frequently used symbols in the vm isolate.
   static void InitOnce(Isolate* isolate);
 
   // Initialize and setup a symbol table for the isolate.
   static void SetupSymbolTable(Isolate* isolate);
 
   // Get number of symbols in an isolate's symbol table.
@@ skipping 43 matching lines @@
   static RawString* predefined_[kMaxPredefined];
 
   friend class SnapshotReader;
 
   DISALLOW_COPY_AND_ASSIGN(Symbols);
 };
 
 }  // namespace dart
 
 #endif  // VM_SYMBOLS_H_