Make enable_service_discovery a chrome/ feature.

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 24e0b4c6c5dccbb5050cc49be511db4f0b4ef9a4..88afa473d3ab30ba07825210928f73ca26b26df0 100644
--- a/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
+++ b/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
@@ -135,7 +135,7 @@
 #include "chrome/browser/spellchecker/spellcheck_factory.h"
 #endif
 
-#if defined(ENABLE_SERVICE_DISCOVERY)
+#if BUILDFLAG(ENABLE_SERVICE_DISCOVERY)
 #include "chrome/browser/printing/cloud_print/privet_notifications_factory.h"
 #endif
 
@@ -244,7 +244,7 @@ EnsureBrowserContextKeyedServiceFactoriesBuilt() {
   InMemoryURLIndexFactory::GetInstance();
   invalidation::ProfileInvalidationProviderFactory::GetInstance();
   InstantServiceFactory::GetInstance();
-#if defined(ENABLE_SERVICE_DISCOVERY)
+#if BUILDFLAG(ENABLE_SERVICE_DISCOVERY)
   cloud_print::PrivetNotificationServiceFactory::GetInstance();
 #endif
 #if defined(ENABLE_SUPERVISED_USERS)