[turbofan] Move SimplifiedOperatorBuilder into JSGraph.

src/compiler/simplified-operator.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_H_
 #define V8_COMPILER_SIMPLIFIED_OPERATOR_H_
 
 #include <iosfwd>
 
 #include "src/compiler/machine-type.h"
@@ skipping 107 matching lines @@
 
 // Additional representations for intermediate code or non-JS code:
 //   - Int64: an untagged signed 64-bit integer
 //   - Uint64: an untagged unsigned 64-bit integer
 //   - Float32: an untagged float32
 
 // Boolean values can be:
 //   - Bool: a tagged pointer to either the canonical JS #false or
 //           the canonical JS #true object
 //   - Bit: an untagged integer 0 or 1, but word-sized
-class SimplifiedOperatorBuilder final {
+class SimplifiedOperatorBuilder final : public ZoneObject {
  public:
   explicit SimplifiedOperatorBuilder(Zone* zone);
 
   const Operator* BooleanNot();
   const Operator* BooleanToNumber();
 
   const Operator* NumberEqual();
   const Operator* NumberLessThan();
   const Operator* NumberLessThanOrEqual();
   const Operator* NumberAdd();
@@ skipping 50 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(SimplifiedOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SIMPLIFIED_OPERATOR_H_