Allow directories for GN data lists.

tools/gn/output_file.h

 // Copyright (c) 2013 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_OUTPUT_FILE_H_
 #define TOOLS_GN_OUTPUT_FILE_H_
 
 #include <string>
 
 #include "base/containers/hash_tables.h"
 #include "tools/gn/build_settings.h"
 
 class SourceFile;
 
 // A simple wrapper around a string that indicates the string is a path
 // relative to the output directory.
 class OutputFile {
  public:
   OutputFile();
-  explicit OutputFile(const base::StringPiece& str);
+  explicit OutputFile(std::string&& v);
+  explicit OutputFile(const std::string& v);
   OutputFile(const BuildSettings* build_settings,
              const SourceFile& source_file);
   ~OutputFile();
 
   std::string& value() { return value_; }
   const std::string& value() const { return value_; }
 
   // Converts to a SourceFile by prepending the build directory to the file.
   // The *Dir version requires that the current OutputFile ends in a slash, and
   // the *File version is the opposite.
@@ skipping 23 matching lines @@
   }
 };
 
 }  // namespace BASE_HASH_NAMESPACE
 
 inline void swap(OutputFile& lhs, OutputFile& rhs) {
   lhs.value().swap(rhs.value());
 }
 
 #endif  // TOOLS_GN_OUTPUT_FILE_H_