Store BundleData paths as SourceDirs rather than strings.

tools/gn/bundle_file_rule.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/bundle_file_rule.h"
 
 #include "tools/gn/output_file.h"
 #include "tools/gn/settings.h"
 #include "tools/gn/substitution_pattern.h"
 #include "tools/gn/substitution_writer.h"
@@ skipping 11 matching lines @@
     const Settings* settings,
     const BundleData& bundle_data,
     const SourceFile& source_file) const {
   std::string output_path;
   for (const auto& subrange : pattern_.ranges()) {
     switch (subrange.type) {
       case SUBSTITUTION_LITERAL:
         output_path.append(subrange.literal);
         break;
       case SUBSTITUTION_BUNDLE_ROOT_DIR:
-        output_path.append(bundle_data.root_dir());
+        output_path.append(bundle_data.root_dir().value());
         break;
       case SUBSTITUTION_BUNDLE_RESOURCES_DIR:
-        output_path.append(bundle_data.resources_dir());
+        output_path.append(bundle_data.resources_dir().value());
         break;
       case SUBSTITUTION_BUNDLE_EXECUTABLE_DIR:
-        output_path.append(bundle_data.executable_dir());
+        output_path.append(bundle_data.executable_dir().value());
         break;
       case SUBSTITUTION_BUNDLE_PLUGINS_DIR:
-        output_path.append(bundle_data.plugins_dir());
+        output_path.append(bundle_data.plugins_dir().value());
         break;
       default:
         output_path.append(SubstitutionWriter::GetSourceSubstitution(
             settings, source_file, subrange.type,
             SubstitutionWriter::OUTPUT_ABSOLUTE, SourceDir()));
         break;
     }
   }
   return SourceFile(SourceFile::SWAP_IN, &output_path);
 }
 
 OutputFile BundleFileRule::ApplyPatternToSourceAsOutputFile(
     const Settings* settings,
     const BundleData& bundle_data,
     const SourceFile& source_file) const {
   return OutputFile(settings->build_settings(),
                     ApplyPatternToSource(settings, bundle_data, source_file));
 }