Remove GN GYP generator.

tools/gn/gyp_helper.h

-// Copyright (c) 2013 The Chromium 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 TOOLS_GN_GYP_HELPER_H_
-#define TOOLS_GN_GYP_HELPER_H_
-
-#include <string>
-
-#include "base/basictypes.h"
-
-class Err;
-class SourceDir;
-class SourceFile;
-class Target;
-
-// Danger this class is NOT threadsafe and reads the targets in a
-// non-threadsafe way, so this should only be used in single-threaded mode.
-class GypHelper {
- public:
-  GypHelper();
-  ~GypHelper();
-
-  SourceFile GetGypFileForTarget(const Target* target, Err* err) const;
-
-  // Returns the name part of the given target. Example "base". This will
-  // include toolchain info for non-default toolchains.
-  std::string GetNameForTarget(const Target* target) const;
-
-  // Returns a full reference to the given target, including the GYP file
-  // and name. Example "<(DEPTH)/base/base.gyp:base".
-  std::string GetFullRefForTarget(const Target* target) const;
-
-  std::string GetFileReference(const SourceFile& file) const;
-  std::string GetDirReference(const SourceDir& dir, bool include_slash) const;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(GypHelper);
-};
-
-#endif  // TOOLS_GN_GYP_HELPER_H_