[turbofan] Cleanup Graph and related classes.

src/compiler/simplified-operator-reducer.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_SIMPLIFIED_OPERATOR_REDUCER_H_
 #define V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_
 
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/simplified-operator.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
+class Factory;
 class Heap;
 
 namespace compiler {
 
 // Forward declarations.
 class CommonOperatorBuilder;
 class JSGraph;
 class MachineOperatorBuilder;
 
 class SimplifiedOperatorReducer FINAL : public Reducer {
@@ skipping 26 matching lines @@
   SimplifiedOperatorBuilder simplified_;
 
   DISALLOW_COPY_AND_ASSIGN(SimplifiedOperatorReducer);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_