Add alias disambiguation for VM fields.

runtime/vm/flow_graph_optimizer.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_FLOW_GRAPH_OPTIMIZER_H_
 #define VM_FLOW_GRAPH_OPTIMIZER_H_
 
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph.h"
 
@@ skipping 380 matching lines @@
 
   void DetachMaterializations();
 
  private:
   void InsertMaterializations(AllocateObjectInstr* alloc);
 
   void CreateMaterializationAt(
       Instruction* exit,
       AllocateObjectInstr* alloc,
       const Class& cls,
-      const ZoneGrowableArray<const Field*>& fields);
+      const ZoneGrowableArray<const Object*>& fields);
 
   FlowGraph* flow_graph_;
 
   GrowableArray<MaterializeObjectInstr*> materializations_;
 };
 
 
 // Optimize spill stores inside try-blocks by identifying values that always
 // contain a single known constant at catch block entry.
 class TryCatchAnalyzer : public AllStatic {
  public:
   static void Optimize(FlowGraph* flow_graph);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_