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

tools/gn/xcode_writer.cc

Index: tools/gn/xcode_writer.cc
diff --git a/tools/gn/xcode_writer.cc b/tools/gn/xcode_writer.cc
index d60f4f77d0c365cdad68c6d3d6c752f552816ad9..e6b66d5b58b43adc61a93935e4f5ffbacb006652 100644
--- a/tools/gn/xcode_writer.cc
+++ b/tools/gn/xcode_writer.cc
@@ -145,7 +145,7 @@ bool XcodeWriter::RunAndWriteFiles(const std::string& workspace_name,
                                    const std::string& ninja_extra_args,
                                    const std::string& dir_filters_string,
                                    const BuildSettings* build_settings,
-                                   Builder* builder,
+                                   const Builder& builder,
                                    Err* err) {
   const XcodeWriter::TargetOsType target_os =
       GetTargetOs(build_settings->build_args());
@@ -180,7 +180,7 @@ bool XcodeWriter::RunAndWriteFiles(const std::string& workspace_name,
     config_name = config_name.substr(0, separator);
 
   std::vector<const Target*> targets;
-  std::vector<const Target*> all_targets = builder->GetAllResolvedTargets();
+  std::vector<const Target*> all_targets = builder.GetAllResolvedTargets();
   if (!XcodeWriter::FilterTargets(build_settings, all_targets,
                                   dir_filters_string, &targets, err)) {
     return false;