Cleanup remaining class/struct fwd declarations

tools/gn/ninja_target_writer.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_NINJA_TARGET_WRITER_H_
 #define TOOLS_GN_NINJA_TARGET_WRITER_H_
 
 #include <iosfwd>
 
 #include "base/macros.h"
 #include "tools/gn/path_output.h"
 #include "tools/gn/substitution_type.h"
 
-class FileTemplate;
 class OutputFile;
 class Settings;
 class Target;
 struct SubstitutionBits;
 
 // Generates one target's ".ninja" file. The toplevel "build.ninja" file is
 // generated by the NinjaBuildWriter.
 class NinjaTargetWriter {
  public:
   NinjaTargetWriter(const Target* target, std::ostream& out);
@@ skipping 36 matching lines @@
   PathOutput path_output_;
 
  private:
   void WriteCopyRules();
   void WriteEscapedSubstitution(SubstitutionType type);
 
   DISALLOW_COPY_AND_ASSIGN(NinjaTargetWriter);
 };
 
 #endif  // TOOLS_GN_NINJA_TARGET_WRITER_H_