[Sync] Introduce ModelError for USS error handling.

components/sync/model/model_type_change_processor.h

Index: components/sync/model/model_type_change_processor.h
diff --git a/components/sync/model/model_type_change_processor.h b/components/sync/model/model_type_change_processor.h
index b001832855e7cbb246aaa2463c023b32ab8a4bdb..cf029084e4d357022fd496126b3c34f1d1db17c6 100644
--- a/components/sync/model/model_type_change_processor.h
+++ b/components/sync/model/model_type_change_processor.h
@@ -12,7 +12,6 @@
 #include "components/sync/engine/activation_context.h"
 #include "components/sync/model/data_type_error_handler.h"
 #include "components/sync/model/entity_data.h"
-#include "components/sync/model/sync_error_factory.h"
 
 namespace syncer {
 
@@ -23,7 +22,7 @@ class SyncError;
 
 // Interface used by the ModelTypeSyncBridge to inform sync of local
 // changes.
-class ModelTypeChangeProcessor : public SyncErrorFactory {
+class ModelTypeChangeProcessor : public DataTypeErrorHandler {
  public:
   typedef base::Callback<void(SyncError, std::unique_ptr<ActivationContext>)>
       StartCallback;