[turbofan] LoadGlobalParameters::slot_index() should just return an int.

src/compiler/js-operator.h

 // Copyright 2013 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_COMPILER_JS_OPERATOR_H_
 #define V8_COMPILER_JS_OPERATOR_H_
 
 #include "src/runtime/runtime.h"
 #include "src/unique.h"
 
@@ skipping 259 matching lines @@
       : name_(name),
         feedback_(feedback),
         typeof_mode_(typeof_mode),
         slot_index_(slot_index) {}
 
   const Unique<Name>& name() const { return name_; }
   TypeofMode typeof_mode() const { return typeof_mode_; }
 
   const VectorSlotPair& feedback() const { return feedback_; }
 
-  const int slot_index() const { return slot_index_; }
+  int slot_index() const { return slot_index_; }
 
  private:
   const Unique<Name> name_;
   const VectorSlotPair feedback_;
   const TypeofMode typeof_mode_;
   const int slot_index_;
 };
 
 bool operator==(LoadGlobalParameters const&, LoadGlobalParameters const&);
 bool operator!=(LoadGlobalParameters const&, LoadGlobalParameters const&);
@@ skipping 256 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(JSOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_JS_OPERATOR_H_