Begin the first small step towards using FilePath everywhere:

base/file_util_linux.cc

 // Copyright (c) 2006-2008 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 "base/file_util.h"
 
 #include <fcntl.h>
 
 #include <string>
 #include <vector>
 
+#include "base/file_path.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 
 namespace file_util {
 
 const wchar_t kPathSeparator = L'/';
 
-bool GetTempDir(std::wstring* path) {
+bool GetTempDir(FilePath* path) {
   const char* tmp = getenv("TMPDIR");
   if (tmp)
-    *path = UTF8ToWide(tmp);
+    *path = FilePath(tmp);
   else
-    *path = L"/tmp";
+    *path = FilePath("/tmp");
   return true;
 }
 
-bool CopyFile(const std::wstring& from_path, const std::wstring& to_path) {
-  int infile = open(WideToUTF8(from_path).c_str(), O_RDONLY);
+bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
+  int infile = open(from_path.value().c_str(), O_RDONLY);
   if (infile < 0)
     return false;
   
-  int outfile = creat(WideToUTF8(to_path).c_str(), 0666);
+  int outfile = creat(to_path.value().c_str(), 0666);
   if (outfile < 0) {
     close(infile);
     return false;
   }
 
   const size_t kBufferSize = 32768;
   std::vector<char> buffer(kBufferSize);
   bool result = true;
 
   while (result) {
@@ skipping 21 matching lines @@
 
   if (close(infile) < 0)
     result = false;
   if (close(outfile) < 0)
     result = false;
 
   return result;
 }
 
 }  // namespace file_util