Remove TLS access for current Zone.

src/deoptimizer.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 577 matching lines @@
   void StoreRegister(Register reg);
   void StoreInt32Register(Register reg);
   void StoreDoubleRegister(DoubleRegister reg);
   void StoreStackSlot(int index);
   void StoreInt32StackSlot(int index);
   void StoreDoubleStackSlot(int index);
   void StoreLiteral(int literal_id);
   void StoreArgumentsObject();
   void MarkDuplicate();
 
-  Zone* zone() { return zone_; }
+  Zone* zone() const { return zone_; }
 
   static int NumberOfOperandsFor(Opcode opcode);
 
 #if defined(OBJECT_PRINT) || defined(ENABLE_DISASSEMBLER)
   static const char* StringFor(Opcode opcode);
 #endif
 
  private:
   TranslationBuffer* buffer_;
   int index_;
@@ skipping 172 matching lines @@
   Object** expression_stack_;
   int source_position_;
 
   friend class Deoptimizer;
 };
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEOPTIMIZER_H_