Enforce WARN_UNUSED_RESULT attribute on Windows

chrome/installer/util/delete_tree_work_item.cc

 // Copyright (c) 2011 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/installer/util/delete_tree_work_item.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/files/file_util.h"
@@ skipping 49 matching lines @@
     base::ScopedTempDir& backup = key_backup_paths_[i];
     if (!ignore_failure_) {
       if (!backup.CreateUniqueTempDirUnderPath(temp_path_)) {
         PLOG(ERROR) << "Could not create temp dir in " << temp_path_.value();
         abort = true;
       } else if (!base::CopyFile(key_file,
                      backup.path().Append(key_file.BaseName()))) {
         PLOG(ERROR) << "Could not back up " << key_file.value()
                     << " to directory " << backup.path().value();
         abort = true;
-        backup.Delete();
+        if (!backup.Delete()) {
+          PLOG(ERROR) << "Could not clean up temp dir in "
+                      << temp_path_.value();
+        }
       }
     }
     if (!abort) {
       HANDLE file = ::CreateFile(key_file.value().c_str(), FILE_ALL_ACCESS,
                                  FILE_SHARE_DELETE, NULL, OPEN_EXISTING, 0,
                                  NULL);
       if (file != INVALID_HANDLE_VALUE) {
         VLOG(1) << "Acquired exclusive lock for key file: " << key_file.value();
         opened_key_files.push_back(file);
       } else {
@@ skipping 74 matching lines @@
           backup_dir.path().Append(key_file.BaseName());
       if (base::PathExists(backup_file) &&
           !base::Move(backup_file, key_file)) {
         // This could happen if we could not delete the key file to begin with.
         PLOG(WARNING) << "Rollback: Failed to move backup file back in place: "
                       << backup_file.value() << " to " << key_file.value();
       }
     }
   }
 }