Add best-effort/allow rollback flags on WorkItem.

chrome/installer/util/work_item_list.h

Index: chrome/installer/util/work_item_list.h
diff --git a/chrome/installer/util/work_item_list.h b/chrome/installer/util/work_item_list.h
index 62351b88e70efb7dd0732ac04f0d08c7d9edf8c8..fe82895a39137324a99f8199e699cd63926925a6 100644
--- a/chrome/installer/util/work_item_list.h
+++ b/chrome/installer/util/work_item_list.h
@@ -28,13 +28,6 @@ class WorkItemList : public WorkItem {
  public:
   ~WorkItemList() override;
 
-  // Execute the WorkItems in the same order as they are added to the list.
-  // It aborts as soon as one WorkItem fails.
-  bool Do() override;
-
-  // Rollback the WorkItems in the reverse order as they are executed.
-  void Rollback() override;
-
   // Add a WorkItem to the list.
   // A WorkItem can only be added to the list before the list's DO() is called.
   // Once a WorkItem is added to the list. The list owns the WorkItem.
@@ -155,6 +148,15 @@ class WorkItemList : public WorkItem {
 
   WorkItemList();
 
+  // WorkItem:
+
+  // Execute the WorkItems in the same order as they are added to the list.
+  // It aborts as soon as one WorkItem fails.
+  bool DoImpl() override;
+
+  // Rollback the WorkItems in the reverse order as they are executed.
+  void RollbackImpl() override;
+
   ListStatus status_;
 
   // The list of WorkItems, in the order of them being added.
@@ -173,13 +175,16 @@ class NoRollbackWorkItemList : public WorkItemList {
  public:
   ~NoRollbackWorkItemList() override;
 
+ private:
+  // WorkItemList:
+
   // Execute the WorkItems in the same order as they are added to the list.
   // If a WorkItem fails, the function will return failure but all other
   // WorkItems will still be executed.
-  bool Do() override;
+  bool DoImpl() override;
 
   // No-op.
-  void Rollback() override;
+  void RollbackImpl() override;
 };
 
 #endif  // CHROME_INSTALLER_UTIL_WORK_ITEM_LIST_H_