Create and cache method extraction stub in the ICData.

runtime/vm/flow_graph.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_H_
 #define VM_FLOW_GRAPH_H_
 
 #include "vm/growable_array.h"
 #include "vm/parser.h"
 
@@ skipping 80 matching lines @@
   }
 
   intptr_t max_block_id() const {
     return max_block_id_;
   }
 
   GraphEntryInstr* graph_entry() const {
     return graph_entry_;
   }
 
+  ConstantInstr* constant_null() const {
+    return constant_null_;
+  }
+
   ZoneGrowableArray<ReturnInstr*>* exits() const { return exits_; }
   void set_exits(ZoneGrowableArray<ReturnInstr*>* exits) { exits_ = exits; }
 
   intptr_t alloc_ssa_temp_index() { return current_ssa_temp_index_++; }
 
   intptr_t InstructionCount() const;
 
   ConstantInstr* AddConstantToInitialDefinitions(const Object& object);
   void AddToInitialDefinitions(Definition* defn);
 
@@ skipping 61 matching lines @@
   const ParsedFunction& parsed_function_;
   const intptr_t num_copied_params_;
   const intptr_t num_non_copied_params_;
   const intptr_t num_stack_locals_;
   GraphEntryInstr* graph_entry_;
   GrowableArray<BlockEntryInstr*> preorder_;
   GrowableArray<BlockEntryInstr*> postorder_;
   GrowableArray<BlockEntryInstr*> reverse_postorder_;
   ZoneGrowableArray<ReturnInstr*>* exits_;
   bool invalid_dominator_tree_;
+  ConstantInstr* constant_null_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_H_