Remove ARGUMENTS_VARIABLE and fix crankshaft to properly detect the arguments object and keep it al…

src/ast/variables.h

 // Copyright 2011 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_AST_VARIABLES_H_
 #define V8_AST_VARIABLES_H_
 
 #include "src/ast/ast-value-factory.h"
 #include "src/globals.h"
 #include "src/zone/zone.h"
@@ skipping 60 matching lines @@
     DCHECK(initialization_flag() != kNeedsInitialization ||
            IsLexicalVariableMode(mode()));
     return initialization_flag() == kNeedsInitialization;
   }
   bool throw_on_const_assignment(LanguageMode language_mode) const {
     return kind() != SLOPPY_FUNCTION_NAME_VARIABLE || is_strict(language_mode);
   }
 
   bool is_function() const { return kind() == FUNCTION_VARIABLE; }
   bool is_this() const { return kind() == THIS_VARIABLE; }
-  bool is_arguments() const { return kind() == ARGUMENTS_VARIABLE; }
   bool is_sloppy_function_name() const {
     return kind() == SLOPPY_FUNCTION_NAME_VARIABLE;
   }
 
   Variable* local_if_not_shadowed() const {
     DCHECK(mode() == DYNAMIC_LOCAL && local_if_not_shadowed_ != NULL);
     return local_if_not_shadowed_;
   }
 
   void set_local_if_not_shadowed(Variable* local) {
@@ skipping 53 matching lines @@
   class InitializationFlagField
       : public BitField16<InitializationFlag, IsUsedField::kNext, 2> {};
   class MaybeAssignedFlagField
       : public BitField16<MaybeAssignedFlag, InitializationFlagField::kNext,
                           2> {};
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_VARIABLES_H_