Deprecte LoweringBuilder in favor of Reducer.

src/compiler/lowering-builder.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_LOWERING_BUILDER_H_
-#define V8_COMPILER_LOWERING_BUILDER_H_
-
-#include "src/v8.h"
-
-#include "src/compiler/graph.h"
-
-
-namespace v8 {
-namespace internal {
-namespace compiler {
-
-// TODO(dcarney): rename this class.
-class LoweringBuilder {
- public:
-  explicit LoweringBuilder(Graph* graph, SourcePositionTable* source_positions);
-  virtual ~LoweringBuilder() {}
-
-  void LowerAllNodes();
-  virtual void Lower(Node* node) = 0;  // Exposed for testing.
-
-  Graph* graph() const { return graph_; }
-
- private:
-  class NodeVisitor;
-  Graph* graph_;
-  SourcePositionTable* source_positions_;
-};
-
-}  // namespace compiler
-}  // namespace internal
-}  // namespace v8
-
-#endif  // V8_COMPILER_LOWERING_BUILDER_H_