[Sync] Refactor non-frontend DTC to handle new API properly.

chrome/browser/sync/glue/preference_data_type_controller.cc

Index: chrome/browser/sync/glue/preference_data_type_controller.cc
diff --git a/chrome/browser/sync/glue/preference_data_type_controller.cc b/chrome/browser/sync/glue/preference_data_type_controller.cc
index 0e52b99b8a895bdc24254db6d0c9e5e7e559da58..e33dd8f938114af48f2a1ae32e1a455eb995af49 100644
--- a/chrome/browser/sync/glue/preference_data_type_controller.cc
+++ b/chrome/browser/sync/glue/preference_data_type_controller.cc
@@ -33,7 +33,12 @@ void PreferenceDataTypeController::CreateSyncComponents() {
       profile_sync_factory_->CreatePreferenceSyncComponents(sync_service_,
                                                             this);
   set_model_associator(sync_components.model_associator);
-  set_change_processor(sync_components.change_processor);
+  change_processor_.reset(reinterpret_cast<GenericChangeProcessor*>(
+      sync_components.change_processor));
+}
+
+ChangeProcessor* PreferenceDataTypeController::change_processor() const {
+  return change_processor_.get();
 }
 
 void PreferenceDataTypeController::RecordUnrecoverableError(