Begin the first small step towards using FilePath everywhere:

base/base_paths.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/base_paths.h"
 
+#include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 
 namespace base {
 
 bool PathProvider(int key, std::wstring* result) {
   // NOTE: DIR_CURRENT is a special cased in PathService::Get
 
-  std::wstring cur;
+  FilePath cur;
   switch (key) {
     case base::DIR_EXE:
       PathService::Get(base::FILE_EXE, &cur);
-      file_util::TrimFilename(&cur);
+      cur = cur.DirName();
       break;
     case base::DIR_MODULE:
       PathService::Get(base::FILE_MODULE, &cur);
-      file_util::TrimFilename(&cur);
+      cur = cur.DirName();
       break;
     case base::DIR_TEMP:
       if (!file_util::GetTempDir(&cur))
         return false;
       break;
     default:
       return false;
   }
 
-  result->swap(cur);
+  *result = cur.ToWStringHack();
   return true;
 }
 
 }  // namespace base