GN: Fix CPU detection in Visual Studio generator

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 <string>
 #include <vector>
@@ skipping 57 matching lines @@
     // Absolute label dir path.
     std::string label_dir_path;
     // Configuration platform. May be different than solution config platform.
     std::string config_platform;
   };
 
   using SolutionProjects = std::vector<SolutionProject*>;
   using SolutionFolders = std::vector<SolutionEntry*>;
 
   explicit VisualStudioWriter(const BuildSettings* build_settings,
+                              bool is_debug_config,
+                              const char* config_platform,
                               Version version);
   ~VisualStudioWriter();
 
   bool WriteProjectFiles(const Target* target, Err* err);
   bool WriteProjectFileContents(std::ostream& out,
                                 const SolutionProject& solution_project,
                                 const Target* target,
                                 Err* err);
   void WriteFiltersFileContents(std::ostream& out, const Target* target);
   bool WriteSolutionFile(Err* err);
@@ skipping 15 matching lines @@
   const char* project_version_;
 
   // Visual Studio version string.
   const char* version_string_;
 
   // Indicates if project files are generated for Debug mode configuration.
   bool is_debug_config_;
 
   // Platform for solution configuration (Win32, x64). Some projects may be
   // configured for different platform.
-  std::string config_platform_;
+  const char* config_platform_;
 
   // All projects contained by solution.
   SolutionProjects projects_;
 
   // Absolute root solution folder path.
   std::string root_folder_path_;
 
   // Folders for all solution projects.
   SolutionFolders folders_;
 
   // 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_