Add stubs for new API triggerPostinstall

Test: th
Bug: 377557752
Change-Id: I73beaae7feebb12d944d59496db2cf8c89115e93
diff --git a/aosp/update_attempter_android.h b/aosp/update_attempter_android.h
index b7851f1..eb3e29f 100644
--- a/aosp/update_attempter_android.h
+++ b/aosp/update_attempter_android.h
@@ -52,7 +52,7 @@
   OTA_SUCCESSFUL,
 };
 
-class UpdateAttempterAndroid
+class UpdateAttempterAndroid final
     : public ServiceDelegateAndroidInterface,
       public ActionProcessorDelegate,
       public DownloadActionDelegate,
@@ -99,6 +99,7 @@
   bool setShouldSwitchSlotOnReboot(const std::string& metadata_filename,
                                    Error* error) override;
   bool resetShouldSwitchSlotOnReboot(Error* error) override;
+  bool TriggerPostinstall(const std::string& partition, Error* error) override;
 
   // ActionProcessorDelegate methods:
   void ProcessingDone(const ActionProcessor* processor,