[GN] Allow Xcode source indexing of non default files.

tools/gn/xcode_writer.cc

 // 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.
 
 #include "tools/gn/xcode_writer.h"
 
 #include <iomanip>
 #include <map>
 #include <memory>
 #include <sstream>
@@ skipping 307 matching lines @@
 
 void XcodeWriter::CreateSourcesProject(
     const std::vector<const Target*>& targets,
     const SourceDir& root_build_dir,
     const PBXAttributes& attributes,
     const std::string& source_path,
     const std::string& config_name,
     TargetOsType target_os) {
   std::vector<SourceFile> sources;
   for (const Target* target : targets) {
-    if (!target->settings()->is_default())
-      continue;
-
     for (const SourceFile& source : target->sources()) {
       if (source.is_system_absolute())
         continue;
 
       if (IsStringInOutputDir(root_build_dir, source.value()))
         continue;
 
       sources.push_back(source);
     }
   }
@@ skipping 84 matching lines @@
     for (const auto& object : pair.second) {
       object->Print(out, 2);
     }
     out << "/* End " << ToString(pair.first) << " section */\n";
   }
 
   out << "\t};\n"
       << "\trootObject = " << project->Reference() << ";\n"
       << "}\n";
 }