Really fix build after r193020.

chrome/browser/extensions/api/file_system/file_system_api.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/api/file_system/file_system_api.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 419 matching lines @@
                 base::Unretained(this), static_cast<void*>(NULL)));
       }
       return;
     }
 
     select_file_dialog_->SelectFile(picker_type,
                                     string16(),
                                     suggested_name,
                                     &file_type_info,
                                     0,
-                                    FILE_PATH_LITERAL(std::string()),
+                                    base::FilePath::StringType(),
                                     owning_window,
                                     NULL);
   }
 
   virtual ~FilePicker() {}
 
  private:
   // ui::SelectFileDialog::Listener implementation.
   virtual void FileSelected(const base::FilePath& path,
                             int index,
@@ skipping 204 matching lines @@
   if (entry_type == WRITABLE && !HasFileSystemWritePermission()) {
     error_ = kRequiresFileSystemWriteError;
     return false;
   }
 
   file_type_info.support_drive = true;
   return ShowPicker(suggested_name, file_type_info, picker_type, entry_type);
 }
 
 }  // namespace extensions