GN: don't write separate files for non-binary targets

tools/gn/qt_creator_writer.h

 // Copyright (c) 2016 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_QT_CREATOR_WRITER_H_
 #define TOOLS_GN_QT_CREATOR_WRITER_H_
 
 #include <set>
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "tools/gn/err.h"
 #include "tools/gn/target.h"
 
 class Builder;
 class BuildSettings;
 
 class QtCreatorWriter {
  public:
   static bool RunAndWriteFile(const BuildSettings* build_settings,
-                              const Builder* builder,
+                              const Builder& builder,
                               Err* err,
                               const std::string& root_target);
 
  private:
   QtCreatorWriter(const BuildSettings* build_settings,
-                  const Builder* builder,
+                  const Builder& builder,
                   const base::FilePath& project_prefix,
                   const std::string& root_target_name);
   ~QtCreatorWriter();
 
   void Run();
 
   bool DiscoverTargets();
   void HandleTarget(const Target* target);
 
   void CollectDeps(const Target* target);
   void AddToSources(const Target::FileList& files);
   void GenerateFile(const base::FilePath::CharType* suffix,
                     const std::set<std::string>& items);
 
   const BuildSettings* build_settings_;
-  const Builder* builder_;
+  const Builder& builder_;
   base::FilePath project_prefix_;
   std::string root_target_name_;
   std::set<const Target*> targets_;
   std::set<std::string> sources_;
   std::set<std::string> includes_;
   std::set<std::string> defines_;
   Err err_;
 
   DISALLOW_COPY_AND_ASSIGN(QtCreatorWriter);
 };
 
 #endif  // TOOLS_GN_QT_CREATOR_WRITER_H_