Remove enable_notifications build flag and define

chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc

Index: chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
diff --git a/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc b/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
index c4f48eb7954d7d991aa401c2cf89531eabcf4514..9e971b2b72431688763f2ddd6280adcd9e4393ba 100644
--- a/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
+++ b/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
@@ -214,12 +214,10 @@ EnsureBrowserContextKeyedServiceFactoriesBuilt() {
 #if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
   CrossDevicePromoFactory::GetInstance();
 #endif
-#if defined(ENABLE_NOTIFICATIONS)
 #if BUILDFLAG(ENABLE_EXTENSIONS)
   ExtensionWelcomeNotificationFactory::GetInstance();
 #endif
   NotifierStateTrackerFactory::GetInstance();
-#endif  // defined(ENABLE_NOTIFICATIONS)
   data_use_measurement::ChromeDataUseAscriberServiceFactory::GetInstance();
   dom_distiller::DomDistillerServiceFactory::GetInstance();
   domain_reliability::DomainReliabilityServiceFactory::GetInstance();