Eliminate RawObject::class_ field entirely.

runtime/vm/snapshot.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/snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
 #include "vm/bootstrap.h"
 #include "vm/exceptions.h"
@@ skipping 350 matching lines @@
   uword address = heap->TryAllocate(size, Heap::kOld);
   if (address == 0) {
     // Use the preallocated out of memory exception to avoid calling
     // into dart code or allocating any code.
     const Instance& exception =
         Instance::Handle(object_store()->out_of_memory());
     Exceptions::Throw(exception);
     UNREACHABLE();
   }
   RawObject* raw_obj = reinterpret_cast<RawObject*>(address + kHeapObjectTag);
-  raw_obj->ptr()->class_ = cls.raw();
   uword tags = 0;
   intptr_t index = cls.id();
   ASSERT(index != kIllegalObjectKind);
   tags = RawObject::ClassIdTag::update(index, tags);
   tags = RawObject::SizeTag::update(size, tags);
   raw_obj->ptr()->tags_ = tags;
   return raw_obj;
 }
 
 
@@ skipping 323 matching lines @@
 
 
 void SnapshotWriterVisitor::VisitPointers(RawObject** first, RawObject** last) {
   for (RawObject** current = first; current <= last; current++) {
     RawObject* raw_obj = *current;
     writer_->WriteObject(raw_obj);
   }
 }
 
 }  // namespace dart