Re-try r29078: Remove some deprecated file_util wstring functions.

chrome_frame/test_utils.h

 // Copyright (c) 2009 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 CHROME_FRAME_TEST_UTILS_H_
 #define CHROME_FRAME_TEST_UTILS_H_
 
 #include <string>
 
+#include "base/file_path.h"
+
 // Helper class used to register different chrome frame DLLs while running
 // tests. At construction, this registers the DLL found in the build path.
 // At destruction, again registers the DLL found in the build path if another
 // DLL has since been registered. Triggers GTEST asserts on failure.
 //
 // TODO(robertshield): Ideally, make this class restore the originally
 // registered chrome frame DLL (e.g. by looking in HKCR) on destruction.
 class ScopedChromeFrameRegistrar {
  public:
   ScopedChromeFrameRegistrar();
   virtual ~ScopedChromeFrameRegistrar();
 
   void RegisterChromeFrameAtPath(const std::wstring& path);
   void RegisterReferenceChromeFrameBuild();
 
   std::wstring GetChromeFrameDllPath() const;
 
-  static std::wstring GetChromeFrameBuildPath();
+  static FilePath GetChromeFrameBuildPath();
   static void RegisterAtPath(const std::wstring& path);
   static void RegisterDefaults();
 
  private:
   // Contains the path of the most recently registered npchrome_tab.dll.
   std::wstring new_chrome_frame_dll_path_;
 
   // Contains the path of the npchrome_tab.dll to be registered at destruction.
   std::wstring original_dll_path_;
 };
 
 #endif  // CHROME_FRAME_TEST_UTILS_H_