Turn app notifications sync to be on by default

chrome/browser/sync/profile_sync_factory_impl.cc

Index: chrome/browser/sync/profile_sync_factory_impl.cc
diff --git a/chrome/browser/sync/profile_sync_factory_impl.cc b/chrome/browser/sync/profile_sync_factory_impl.cc
index a8204195eb51f56a0cf73e98624b30885f8617e4..c31e2c61ed2efea6f20d8455fc22d1871b9a8bf2 100644
--- a/chrome/browser/sync/profile_sync_factory_impl.cc
+++ b/chrome/browser/sync/profile_sync_factory_impl.cc
@@ -183,9 +183,9 @@ void ProfileSyncFactoryImpl::RegisterDataTypes(ProfileSyncService* pss) {
         new AutofillProfileDataTypeController(this, profile_));
   }
 
-  // App notifications sync is disabled by default.  Register only if
-  // explicitly enabled.
-  if (command_line_->HasSwitch(switches::kEnableSyncAppNotifications)) {
+  // App notifications sync is enabled by default.  Register only if
+  // explicitly disabled.
+  if (!command_line_->HasSwitch(switches::kDisableSyncAppNotifications)) {
     pss->RegisterDataTypeController(
         new AppNotificationDataTypeController(this, profile_, pss));
   }