[USS] Add function for update storage key for processor

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 e4208100d1e8a08d2e677aeb7c9d422184546394..78d00a3974172ba99c1f306fbb0022ff0f6b0655 100644
--- a/components/sync/model/model_type_change_processor.h
+++ b/components/sync/model/model_type_change_processor.h
@@ -48,6 +48,14 @@ class ModelTypeChangeProcessor {
   virtual void Delete(const std::string& storage_key,
                       MetadataChangeList* metadata_change_list) = 0;
 
+  // Inform the processor that storage key has chagned.
+  // TODO(gangwu): crbug.com/719570 should remove this after bug fixed.
+  // This function should only be called for the data type which does not create
+  // storage key based on syncer::EntityData.
+  virtual void UpdateStorageKey(const std::string& old_storage_key,
+                                const std::string& new_storage_key,
+                                MetadataChangeList* metadata_change_list) = 0;
+
   // The bridge is expected to call this exactly once unless it encounters an
   // error. Ideally ModelReadyToSync() is called as soon as possible during
   // initialization, and must be called before invoking either Put() or