[turbofan] Next step towards shared operators.

src/compiler/js-graph.h

 // Copyright 2014 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_GRAPH_H_
 #define V8_COMPILER_JS_GRAPH_H_
 
 #include "src/compiler/common-node-cache.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
@@ skipping 81 matching lines @@
   SetOncePointer<Node> false_constant_;
   SetOncePointer<Node> null_constant_;
   SetOncePointer<Node> zero_constant_;
   SetOncePointer<Node> one_constant_;
   SetOncePointer<Node> nan_constant_;
 
   CommonNodeCache cache_;
 
   Node* ImmovableHeapConstant(Handle<Object> value);
   Node* NumberConstant(double value);
-  Node* NewNode(Operator* op);
+  Node* NewNode(const Operator* op);
 
   Factory* factory() { return isolate()->factory(); }
 };
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif