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

tools/gn/visual_studio_writer.h

 // Copyright 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_VISUAL_STUDIO_WRITER_H_
 #define TOOLS_GN_VISUAL_STUDIO_WRITER_H_
 
 #include <iosfwd>
 #include <memory>
 #include <string>
@@ skipping 19 matching lines @@
     Vs2013 = 1,  // Visual Studio 2013
     Vs2015       // Visual Studio 2015
   };
 
   // Writes Visual Studio project and solution files. |sln_name| is the optional
   // solution file name ("all" is used if not specified). |dir_filters| is
   // optional semicolon-separated list of label patterns used to limit the set
   // of generated projects. Only matching targets will be included to the
   // solution. On failure will populate |err| and will return false.
   static bool RunAndWriteFiles(const BuildSettings* build_settings,
-                               Builder* builder,
+                               const Builder& builder,
                                Version version,
                                const std::string& sln_name,
                                const std::string& dir_filters,
                                Err* err);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(VisualStudioWriterTest, ResolveSolutionFolders);
   FRIEND_TEST_ALL_PREFIXES(VisualStudioWriterTest,
                            ResolveSolutionFolders_AbsPath);
 
@@ skipping 93 matching lines @@
   // Semicolon-separated Windows SDK include directories.
   std::string windows_kits_include_dirs_;
 
   // Path formatter for ninja targets.
   PathOutput ninja_path_output_;
 
   DISALLOW_COPY_AND_ASSIGN(VisualStudioWriter);
 };
 
 #endif  // TOOLS_GN_VISUAL_STUDIO_WRITER_H_