Add Zone-based handle allocation interface and reduce use of Isolate-based interfaces.

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 236 matching lines @@
                                     Definition* right_instr);
   void TryMergeTruncDivMod(GrowableArray<BinarySmiOpInstr*>* merge_candidates);
   void TryMergeMathUnary(GrowableArray<MathUnaryInstr*>* merge_candidates);
 
   void AppendLoadIndexedForMerged(Definition* instr, intptr_t ix, intptr_t cid);
   void AppendExtractNthOutputForMerged(Definition* instr, intptr_t ix,
                                        Representation rep, intptr_t cid);
   bool TryStringLengthOneEquality(InstanceCallInstr* call, Token::Kind op_kind);
 
   Isolate* isolate() const { return flow_graph_->isolate(); }
+  Zone* zone() const { return flow_graph_->zone(); }
 
   FlowGraph* flow_graph_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
 };
 
 
 // Loop invariant code motion.
 class LICM : public ValueObject {
  public:
@@ skipping 137 matching lines @@
   void InsertMaterializations(Definition* alloc);
 
   void CreateMaterializationAt(
       Instruction* exit,
       Definition* alloc,
       const ZoneGrowableArray<const Object*>& fields);
 
   void EliminateAllocation(Definition* alloc);
 
   Isolate* isolate() const { return flow_graph_->isolate(); }
+  Zone* zone() const { return flow_graph_->zone(); }
 
   FlowGraph* flow_graph_;
 
   GrowableArray<Definition*> candidates_;
   GrowableArray<MaterializeObjectInstr*> materializations_;
 
   ExitsCollector exits_collector_;
 };
 
 
 // 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_