GN support for generating VS2013 project files

tools/gn/visual_studio_writer.cc

Index: tools/gn/visual_studio_writer.cc
diff --git a/tools/gn/visual_studio_writer.cc b/tools/gn/visual_studio_writer.cc
index dec083753f79052cdc6a8a0ef80a75cfacf5d739..b0392b41eacd7d2dc6d2574e7218c0cbe1580602 100644
--- a/tools/gn/visual_studio_writer.cc
+++ b/tools/gn/visual_studio_writer.cc
@@ -64,8 +64,12 @@ struct SourceFileWriter {
   const SourceFile& source_file_;
 };
 
-const char kToolsetVersion[] = "v140";                     // Visual Studio 2015
-const char kVisualStudioVersion[] = "14.0";                // Visual Studio 2015
+const char kToolsetVersionVs2013[] = "v120";               // Visual Studio 2013
+const char kToolsetVersionVs2015[] = "v140";               // Visual Studio 2015
+const char kProjectVersionVs2013[] = "12.0";               // Visual Studio 2013
+const char kProjectVersionVs2015[] = "14.0";               // Visual Studio 2015
+const char kVersionStringVs2013[] = "Visual Studio 2013";  // Visual Studio 2013
+const char kVersionStringVs2015[] = "Visual Studio 2015";  // Visual Studio 2015
 const char kWindowsKitsVersion[] = "10";                   // Windows 10 SDK
 const char kWindowsKitsIncludeVersion[] = "10.0.10240.0";  // Windows 10 SDK
 
@@ -173,7 +177,8 @@ VisualStudioWriter::SolutionProject::SolutionProject(
 
 VisualStudioWriter::SolutionProject::~SolutionProject() = default;
 
-VisualStudioWriter::VisualStudioWriter(const BuildSettings* build_settings)
+VisualStudioWriter::VisualStudioWriter(const BuildSettings* build_settings,
+                                       Version version)
     : build_settings_(build_settings) {
   const Value* value = build_settings->build_args().GetArgOverride("is_debug");
   is_debug_config_ = value == nullptr || value->boolean_value();
@@ -182,6 +187,21 @@ VisualStudioWriter::VisualStudioWriter(const BuildSettings* build_settings)
   if (value != nullptr && value->string_value() == "x64")
     config_platform_ = "x64";
 
+  switch (version) {
+    case Version::Vs2013:
+      project_version_ = kProjectVersionVs2013;
+      toolset_version_ = kToolsetVersionVs2013;
+      version_string_ = kVersionStringVs2013;
+      break;
+    case Version::Vs2015:
+      project_version_ = kProjectVersionVs2015;
+      toolset_version_ = kToolsetVersionVs2015;
+      version_string_ = kVersionStringVs2015;
+      break;
+    default:
+      NOTREACHED() << "Not a valid Visual Studio Version: " << version;
+  }
+
   windows_kits_include_dirs_ = GetWindowsKitsIncludeDirs();
 }
 
@@ -193,10 +213,11 @@ VisualStudioWriter::~VisualStudioWriter() {
 // static
 bool VisualStudioWriter::RunAndWriteFiles(const BuildSettings* build_settings,
                                           Builder* builder,
+                                          Version version,
                                           Err* err) {
   std::vector<const Target*> targets = builder->GetAllResolvedTargets();
 
-  VisualStudioWriter writer(build_settings);
+  VisualStudioWriter writer(build_settings, version);
   writer.projects_.reserve(targets.size());
   writer.folders_.reserve(targets.size());
 
@@ -290,7 +311,7 @@ bool VisualStudioWriter::WriteProjectFileContents(
   XmlElementWriter project(
       out, "Project",
       XmlAttributes("DefaultTargets", "Build")
-          .add("ToolsVersion", kVisualStudioVersion)
+          .add("ToolsVersion", project_version_)
           .add("xmlns", "http://schemas.microsoft.com/developer/msbuild/2003"));
 
   {
@@ -333,7 +354,7 @@ bool VisualStudioWriter::WriteProjectFileContents(
   {
     scoped_ptr<XmlElementWriter> locals =
         project.SubElement("PropertyGroup", XmlAttributes("Label", "Locals"));
-    locals->SubElement("PlatformToolset")->Text(kToolsetVersion);
+    locals->SubElement("PlatformToolset")->Text(toolset_version_);
   }
 
   project.SubElement(
@@ -580,7 +601,7 @@ void VisualStudioWriter::WriteSolutionFileContents(
     const base::FilePath& solution_dir_path) {
   out << "Microsoft Visual Studio Solution File, Format Version 12.00"
       << std::endl;
-  out << "# Visual Studio 2015" << std::endl;
+  out << "# " << version_string_ << std::endl;
 
   SourceDir solution_dir(FilePathToUTF8(solution_dir_path));
   for (const SolutionEntry* folder : folders_) {