Added read-only file error test.

base/test/test_file_util_win.cc

Index: base/test/test_file_util_win.cc
diff --git a/base/test/test_file_util_win.cc b/base/test/test_file_util_win.cc
index 70ca907f7b431634eb5e38a959c48c9210e07878..22b884b17496dc8b57a0f0839db207749cbfa45f 100644
--- a/base/test/test_file_util_win.cc
+++ b/base/test/test_file_util_win.cc
@@ -23,6 +23,11 @@ static const ptrdiff_t kOneMB = 1024 * 1024;
 
 namespace {
 
+struct PermissionInfo {
+  PSECURITY_DESCRIPTOR security_descriptor;
+  ACL dacl;
+};
+
 // Deny |permission| on the file |path|, for the current user.
 bool DenyFilePermission(const FilePath& path, DWORD permission) {
   PACL old_dacl;
@@ -278,4 +283,42 @@ bool MakeFileUnwritable(const FilePath& path) {
   return DenyFilePermission(path, GENERIC_WRITE);
 }
 
+void* GetPermissionInfo(const FilePath& path, size_t* length) {
+  DCHECK(length != NULL);
+  *length = 0;
+  PACL dacl = NULL;
+  PSECURITY_DESCRIPTOR security_descriptor;
+  if (GetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
+                           SE_FILE_OBJECT,
+                           DACL_SECURITY_INFORMATION, NULL, NULL, &dacl,
+                           NULL, &security_descriptor) != ERROR_SUCCESS) {
+    return NULL;
+  }
+  DCHECK(dacl != NULL);
+
+  *length = sizeof(PSECURITY_DESCRIPTOR) + dacl->AclSize;
+  PermissionInfo* info = reinterpret_cast<PermissionInfo*>(new char[*length]);
+  info->security_descriptor = security_descriptor;
+  memcpy(&info->dacl, dacl, dacl->AclSize);
+
+  return info;
+}
+
+bool RestorePermissionInfo(const FilePath& path, void* info, size_t length) {
+  if (!info || !length)
+    return false;
+
+  PermissionInfo* perm = reinterpret_cast<PermissionInfo*>(info);
+
+  DWORD rc = SetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
+                                  SE_FILE_OBJECT, DACL_SECURITY_INFORMATION,
+                                  NULL, NULL, &perm->dacl, NULL);
+  LocalFree(perm->security_descriptor);
+
+  char* char_array = reinterpret_cast<char*>(info);
+  delete [] char_array;
+
+  return rc == ERROR_SUCCESS;
+}
+
 }  // namespace file_util