Revert of [crankshaft] Fixing ES6 tail call elimination.

src/crankshaft/lithium.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_CRANKSHAFT_LITHIUM_H_
 #define V8_CRANKSHAFT_LITHIUM_H_
 
 #include <set>
 
 #include "src/allocation.h"
@@ skipping 727 matching lines @@
 
   bool is_unused() const { return status_ == UNUSED; }
   bool is_building() const { return status_ == BUILDING; }
   bool is_done() const { return status_ == DONE; }
   bool is_aborted() const { return status_ == ABORTED; }
 
   // An input operand in register, stack slot or a constant operand.
   // Will not be moved to a register even if one is freely available.
   virtual MUST_USE_RESULT LOperand* UseAny(HValue* value) = 0;
 
-  // Assigns given environment to an instruction.  An instruction which can
-  // deoptimize must have an environment.
-  LInstruction* AssignEnvironment(LInstruction* instr,
-                                  HEnvironment* hydrogen_env);
-
   LEnvironment* CreateEnvironment(HEnvironment* hydrogen_env,
                                   int* argument_index_accumulator,
                                   ZoneList<HValue*>* objects_to_materialize);
   void AddObjectToMaterialize(HValue* value,
                               ZoneList<HValue*>* objects_to_materialize,
                               LEnvironment* result);
 
   Zone* zone() const { return zone_; }
 
   int argument_count_;
@@ skipping 79 matching lines @@
   InputIterator input_iterator_;
   DeepIterator env_iterator_;
 };
 
 class LInstruction;
 class LCodeGen;
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CRANKSHAFT_LITHIUM_H_