Add best-effort/allow rollback flags on WorkItem.

chrome/installer/util/create_reg_key_work_item.cc

Index: chrome/installer/util/create_reg_key_work_item.cc
diff --git a/chrome/installer/util/create_reg_key_work_item.cc b/chrome/installer/util/create_reg_key_work_item.cc
index 431963146284d1cffd172bc4e3f4bbbf2fe0f302..dbf46b2058dd9399282c3a029667e0c9e1b8503e 100644
--- a/chrome/installer/util/create_reg_key_work_item.cc
+++ b/chrome/installer/util/create_reg_key_work_item.cc
@@ -46,7 +46,7 @@ CreateRegKeyWorkItem::CreateRegKeyWorkItem(HKEY predefined_root,
          wow64_access == KEY_WOW64_64KEY);
 }
 
-bool CreateRegKeyWorkItem::Do() {
+bool CreateRegKeyWorkItem::DoImpl() {
   if (!InitKeyList()) {
     // Nothing needs to be done here.
     VLOG(1) << "no key to create";
@@ -90,7 +90,7 @@ bool CreateRegKeyWorkItem::Do() {
   return true;
 }
 
-void CreateRegKeyWorkItem::Rollback() {
+void CreateRegKeyWorkItem::RollbackImpl() {
   if (!key_created_)
     return;