Bug 1476674 - Fix crash in nsNavHistory::RecalculateOriginFrecencyStats r=mak

Differential Revision: https://phabricator.services.mozilla.com/D2232

--HG--
extra : moz-landing-system : lando

toolkit/components/places/Database.cpp

@@ -2728,8 +2728,10 @@ Database::MigrateV52OriginFrecencies()
     new MigrateV52OriginFrecenciesRunnable(mMainConn));
   nsCOMPtr<nsIEventTarget> target(do_GetInterface(mMainConn));
   MOZ_ASSERT(target);
+  if (target) {
     Unused << target->Dispatch(runnable, NS_DISPATCH_NORMAL);
   }
+}
 
 nsresult
 Database::MigrateV52Up()

toolkit/components/places/nsNavHistory.cpp

@@ -714,9 +714,8 @@ nsNavHistory::RecalculateOriginFrecencyStats(nsIObserver *aCallback)
     )
   );
 
-  nsCOMPtr<mozIStorageConnection> conn = mDB->MainConn();
-  nsCOMPtr<nsIEventTarget> target = do_GetInterface(conn);
-  MOZ_ASSERT(target);
+  nsCOMPtr<nsIEventTarget> target(do_GetInterface(mDB->MainConn()));
+  NS_ENSURE_STATE(target);
   nsresult rv = target->Dispatch(NS_NewRunnableFunction(
     "nsNavHistory::RecalculateOriginFrecencyStats",
     [self, callback] {