Avoid reading RawObject::class_ directly in the runtime.

runtime/vm/heap.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/heap.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/compiler_stats.h"
 #include "vm/flags.h"
@@ skipping 115 matching lines @@
 
 void Heap::IterateCodePointers(ObjectPointerVisitor* visitor) {
   code_space_->VisitObjectPointers(visitor);
 }
 
 
 RawInstructions* Heap::FindObjectInCodeSpace(FindObjectVisitor* visitor) {
   // The code heap can only have RawInstructions objects.
   RawObject* raw_obj = code_space_->FindObject(visitor);
   ASSERT((raw_obj == Object::null()) ||
-         (raw_obj->ptr()->class_->ptr()->instance_kind_ == kInstructions));
+         (raw_obj->GetClassIndex() == kInstructions));
   return reinterpret_cast<RawInstructions*>(raw_obj);
 }
 
 
 void Heap::CollectGarbage(Space space, ApiCallbacks api_callbacks) {
   bool invoke_api_callbacks = (api_callbacks == kInvokeApiCallbacks);
   switch (space) {
     case kNew:
       new_space_->Scavenge(invoke_api_callbacks);
       break;
@@ skipping 71 matching lines @@
   isolate()->IncrementNoGCScopeDepth();
 }
 
 
 NoGCScope::~NoGCScope() {
   isolate()->DecrementNoGCScopeDepth();
 }
 #endif  // defined(DEBUG)
 
 }  // namespace dart