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

chrome/installer/util/set_reg_value_work_item.h

Index: chrome/installer/util/set_reg_value_work_item.h
diff --git a/chrome/installer/util/set_reg_value_work_item.h b/chrome/installer/util/set_reg_value_work_item.h
index c8fdc2b8b935706915f49e46910e56f60fab0fe5..60104c4e9c89133231adac143a241456c73f498a 100644
--- a/chrome/installer/util/set_reg_value_work_item.h
+++ b/chrome/installer/util/set_reg_value_work_item.h
@@ -49,6 +49,10 @@
 
   ~SetRegValueWorkItem() override;
 
+  bool Do() override;
+
+  void Rollback() override;
+
  private:
   enum SettingStatus {
     // The status before Do is called.
@@ -65,10 +69,6 @@
     // The status after Do and Rollback is called.
     VALUE_ROLL_BACK
   };
-
-  // 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.