Sync: Turn on full history sync by default.

chrome/browser/sync/profile_sync_components_factory_impl.cc

Index: chrome/browser/sync/profile_sync_components_factory_impl.cc
diff --git a/chrome/browser/sync/profile_sync_components_factory_impl.cc b/chrome/browser/sync/profile_sync_components_factory_impl.cc
index 9049b7627877f1948ec72295b3ea8ecec8225131..6cf9b9b6bf5506fbbd8adb45f3dfa2c490c88539 100644
--- a/chrome/browser/sync/profile_sync_components_factory_impl.cc
+++ b/chrome/browser/sync/profile_sync_components_factory_impl.cc
@@ -146,11 +146,9 @@ void ProfileSyncComponentsFactoryImpl::RegisterCommonDataTypes(
         new TypedUrlDataTypeController(this, profile_, pss));
   }
 
-  // Unless it is explicitly disabled, history delete directive sync is
-  // enabled whenever full history sync is enabled.
-  if (command_line_->HasSwitch(switches::kHistoryEnableFullHistorySync) &&
-      !command_line_->HasSwitch(
-          switches::kDisableSyncHistoryDeleteDirectives)) {
+  // Delete directive sync is enabled by default.  Register unless full history
+  // sync is disabled.
+  if (!command_line_->HasSwitch(switches::kHistoryDisableFullHistorySync)) {
     pss->RegisterDataTypeController(
         new UIDataTypeController(
             syncer::HISTORY_DELETE_DIRECTIVES, this, profile_, pss));