Add best-effort/allow rollback flags on WorkItem.

chrome/installer/util/delete_reg_key_work_item.cc

 // 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.
 
 #include "chrome/installer/util/delete_reg_key_work_item.h"
 
 #include <shlwapi.h>
 
 #include "base/logging.h"
 #include "base/win/registry.h"
@@ skipping 11 matching lines @@
       path_(path),
       wow64_access_(wow64_access) {
   DCHECK(predefined_root);
   // It's a safe bet that we don't want to delete one of the root trees.
   DCHECK(!path.empty());
   DCHECK(wow64_access == 0 ||
          wow64_access == KEY_WOW64_32KEY ||
          wow64_access == KEY_WOW64_64KEY);
 }
 
-bool DeleteRegKeyWorkItem::Do() {
+bool DeleteRegKeyWorkItem::DoImpl() {
+  DCHECK(!backup_initialized_);
+
   if (path_.empty())
     return false;
 
-  RegistryKeyBackup backup;
-
-  // Only try to make a backup if we're not configured to ignore failures.
-  if (!ignore_failure_) {
-    if (!backup.Initialize(predefined_root_, path_.c_str(), wow64_access_)) {
+  // Only try to make a backup if rollback is enabled.
+  if (rollback_enabled()) {
+    if (!backup_.Initialize(predefined_root_, path_.c_str(), wow64_access_)) {
       LOG(ERROR) << "Failed to backup destination for registry key copy.";
       return false;
     }
+    backup_initialized_ = true;
   }
 
   // Delete the key.
   if (!InstallUtil::DeleteRegistryKey(
           predefined_root_, path_.c_str(), wow64_access_)) {
-    return ignore_failure_;
+    return false;
   }
 
-  // We've succeeded, so remember any backup we may have made.
-  backup_.swap(backup);
-
   return true;
 }
 
-void DeleteRegKeyWorkItem::Rollback() {
-  if (ignore_failure_)
+void DeleteRegKeyWorkItem::RollbackImpl() {
+  if (!backup_initialized_)
     return;
 
   // Delete anything in the key before restoring the backup in case someone else
   // put new data in the key after Do().
   InstallUtil::DeleteRegistryKey(predefined_root_,
                                  path_.c_str(),
                                  wow64_access_);
 
   // Restore the old contents.  The restoration takes on its default security
   // attributes; any custom attributes are lost.
   if (!backup_.WriteTo(predefined_root_, path_.c_str(), wow64_access_))
     LOG(ERROR) << "Failed to restore key in rollback.";
 }