Revert r20998.

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"
 
 namespace dart {
 
 template <typename T> class GrowableArray;
 template <typename T> class DirectChainedHashMap;
 template <typename T> class PointerKeyValueTrait;
 
 class FlowGraphOptimizer : public FlowGraphVisitor {
  public:
-  FlowGraphOptimizer(FlowGraph* flow_graph,
-                     GrowableArray<Field*>* guarded_fields)
+  explicit FlowGraphOptimizer(FlowGraph* flow_graph)
       : FlowGraphVisitor(flow_graph->reverse_postorder()),
-        flow_graph_(flow_graph),
-        guarded_fields_(guarded_fields) { }
+        flow_graph_(flow_graph) { }
   virtual ~FlowGraphOptimizer() {}
 
   FlowGraph* flow_graph() const { return flow_graph_; }
 
   // Use ICData to optimize, replace or eliminate instructions.
   void ApplyICData();
 
   // Use propagated class ids to optimize, replace or eliminate instructions.
   void ApplyClassIds();
 
@@ skipping 119 matching lines @@
   // comparison itself or a branch on the comparison.
   template <typename T>
   void HandleEqualityCompare(EqualityCompareInstr* comp,
                              T current_instruction);
 
   void OptimizeLeftShiftBitAndSmiOp(Definition* bit_and_instr,
                                     Definition* left_instr,
                                     Definition* right_instr);
 
   FlowGraph* flow_graph_;
-  GrowableArray<Field*>* guarded_fields_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
 };
 
 
 class ParsedFunction;
 
 
 // Loop invariant code motion.
 class LICM : public ValueObject {
@@ skipping 124 matching lines @@
   // inputs.
   static BranchInstr* CloneBranch(BranchInstr* branch,
                                   Value* left,
                                   Value* right);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_