[turbofan] Remove usage of Unique<T> from graph.

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 27 matching lines @@
   Node* CEntryStubConstant(int result_size);
   Node* UndefinedConstant();
   Node* TheHoleConstant();
   Node* TrueConstant();
   Node* FalseConstant();
   Node* NullConstant();
   Node* ZeroConstant();
   Node* OneConstant();
   Node* NaNConstant();
 
-  // Creates a HeapConstant node, possibly canonicalized, without inspecting the
-  // object.
-  Node* HeapConstant(Unique<HeapObject> value);
-
   // Creates a HeapConstant node, possibly canonicalized, and may access the
   // heap to inspect the object.
   Node* HeapConstant(Handle<HeapObject> value);
 
   // Creates a Constant node of the appropriate type for the given object.
   // Accesses the heap to inspect the object and determine whether one of the
   // canonicalized globals or a number constant should be returned.
   Node* Constant(Handle<Object> value);
 
   // Creates a NumberConstant node, usually canonicalized.
@@ skipping 96 matching lines @@
   Node* NumberConstant(double value);
 
   DISALLOW_COPY_AND_ASSIGN(JSGraph);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif