Clear token streams before compacting the symbol table.

runtime/vm/object.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_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 3433 matching lines @@
   void set_url(const String& value) const;
   void set_source(const String& value) const;
   void set_kind(RawScript::Kind value) const;
   void set_load_timestamp(int64_t value) const;
   void set_tokens(const TokenStream& value) const;
 
   static RawScript* New();
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(Script, Object);
   friend class Class;
+  friend class Precompiler;
 };
 
 
 class DictionaryIterator : public ValueObject {
  public:
   explicit DictionaryIterator(const Library& library);
 
   bool HasNext() const { return next_ix_ < size_; }
 
   // Returns next non-null raw object.
@@ skipping 5193 matching lines @@
 
 inline void TypeArguments::SetHash(intptr_t value) const {
   // This is only safe because we create a new Smi, which does not cause
   // heap allocation.
   StoreSmi(&raw_ptr()->hash_, Smi::New(value));
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_