Implemented schema change for the isolate reload operation.

runtime/vm/become.h

 // Copyright (c) 2016, 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_BECOME_H_
 #define VM_BECOME_H_
 
 #include "vm/allocation.h"
 #include "vm/raw_object.h"
 
@@ skipping 62 matching lines @@
 
 // TODO(johnmccutchan): Refactor this class so that it is not all static and
 // provides utility methods for building the mapping of before and after.
 class Become : public AllStatic {
  public:
   // Smalltalk's one-way bulk become (Array>>#elementsForwardIdentityTo:).
   // Redirects all pointers to elements of 'before' to the corresponding element
   // in 'after'. Every element in 'before' is guaranteed to be not reachable.
   // Useful for atomically applying behavior and schema changes.
   static void ElementsForwardIdentity(const Array& before, const Array& after);
+
+  // Convert and instance object into a dummy object,
+  // making the instance independent of its class.
+  // (used for morphic instances during reload).
+  static void MakeDummyObject(const Instance& instance);
 };
 
 }  // namespace dart
 
 #endif  // VM_BECOME_H_