Added read-only file error test.

base/test/test_file_util.h

 // Copyright (c) 2010 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 BASE_TEST_TEST_FILE_UTIL_H_
 #define BASE_TEST_TEST_FILE_UTIL_H_
 #pragma once
 
 // File utility functions used only by tests.
 
 #include <string>
 
 #include "base/compiler_specific.h"
+#include "base/file_path.h"
 
 class FilePath;
 
 namespace file_util {
 
 // Wrapper over file_util::Delete. On Windows repeatedly invokes Delete in case
 // of failure to workaround Windows file locking semantics. Returns true on
 // success.
 bool DieFileDie(const FilePath& file, bool recurse);
 
@@ skipping 25 matching lines @@
 // string16 elsewhere for Unicode strings, but in tests it is frequently
 // convenient to be able to compare paths to literals like L"foobar".
 std::wstring FilePathAsWString(const FilePath& path);
 FilePath WStringAsFilePath(const std::wstring& path);
 
 // For testing, make the file unreadable or unwritable.
 // In POSIX, this does not apply to the root user.
 bool MakeFileUnreadable(const FilePath& path) WARN_UNUSED_RESULT;
 bool MakeFileUnwritable(const FilePath& path) WARN_UNUSED_RESULT;
 
+// Saves the current permissions for a path, and restores it on destruction.
+class PermissionRestorer {
+ public:
+  explicit PermissionRestorer(const FilePath& path);
+  ~PermissionRestorer();
+
+ private:
+  const FilePath path_;
+  void* info_;  // The opaque stored permission information.
+  size_t length_;  // The length of the stored permission information.
+
+  DISALLOW_COPY_AND_ASSIGN(PermissionRestorer);
+};
+
 }  // namespace file_util
 
 #endif  // BASE_TEST_TEST_FILE_UTIL_H_