Revert of Add best-effort/allow rollback flags on WorkItem.

chrome/installer/util/delete_reg_value_work_item.h

Index: chrome/installer/util/delete_reg_value_work_item.h
diff --git a/chrome/installer/util/delete_reg_value_work_item.h b/chrome/installer/util/delete_reg_value_work_item.h
index 440780db422827f12f3b606d09ec7f1555ee8b33..f1bd50a9b7123c96618b16f03edf63597d4b4380 100644
--- a/chrome/installer/util/delete_reg_value_work_item.h
+++ b/chrome/installer/util/delete_reg_value_work_item.h
@@ -17,6 +17,10 @@
 class DeleteRegValueWorkItem : public WorkItem {
  public:
   ~DeleteRegValueWorkItem() override;
+
+  bool Do() override;
+
+  void Rollback() override;
 
  private:
   friend class WorkItem;
@@ -39,10 +43,6 @@
                          REGSAM wow64_acccess,
                          const std::wstring& value_name);
 
-  // WorkItem:
-  bool DoImpl() override;
-  void RollbackImpl() override;
-
   // Root key of the target key under which the value is set. The root key can
   // only be one of the predefined keys on Windows.
   HKEY predefined_root_;