Reclaim the CreatedFromSnapshot bit and use it to indicate VM Heap object

runtime/vm/dart_api_message.cc

 // 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.
 
 #include "vm/dart_api_message.h"
 #include "vm/object.h"
 #include "vm/snapshot_ids.h"
 #include "vm/symbols.h"
 #include "vm/unicode.h"
 
@@ skipping 517 matching lines @@
   }
   // No other VM isolate objects are supported.
   return AllocateDartCObjectNull();
 }
 
 
 Dart_CObject* ApiMessageReader::ReadInternalVMObject(intptr_t class_id,
                                                      intptr_t object_id) {
   switch (class_id) {
     case kClassCid: {
+      Read<bool>();  // Consume the is_in_fullsnapshot indicator.
       Dart_CObject_Internal* object = AllocateDartCObjectClass();
       AddBackRef(object_id, object, kIsDeserialized);
       object->internal.as_class.library_url = ReadObjectImpl();
       ASSERT(object->internal.as_class.library_url->type ==
              Dart_CObject_kString);
       object->internal.as_class.class_name = ReadObjectImpl();
       ASSERT(object->internal.as_class.class_name->type ==
              Dart_CObject_kString);
       return object;
     }
@@ skipping 767 matching lines @@
     if (!success) {
       UnmarkAllCObjects(object);
       return false;
     }
   }
   UnmarkAllCObjects(object);
   return true;
 }
 
 }  // namespace dart