[Sync] Migrate bridge implementations to change list based MergeSyncData

components/sync/model/fake_model_type_sync_bridge.cc

Index: components/sync/model/fake_model_type_sync_bridge.cc
diff --git a/components/sync/model/fake_model_type_sync_bridge.cc b/components/sync/model/fake_model_type_sync_bridge.cc
index 5c0cb83f0f76ffe46298606db0ce8c650561881d..538fba0f337b0f7985798253737b9974d6fe94cc 100644
--- a/components/sync/model/fake_model_type_sync_bridge.cc
+++ b/components/sync/model/fake_model_type_sync_bridge.cc
@@ -232,13 +232,6 @@ base::Optional<ModelError> FakeModelTypeSyncBridge::MergeSyncData(
   return {};
 }
 
-base::Optional<ModelError> FakeModelTypeSyncBridge::MergeSyncData(
-    std::unique_ptr<MetadataChangeList> metadata_change_list,
-    EntityDataMap entity_data) {
-  NOTREACHED();
-  return {};
-}
-
 base::Optional<ModelError> FakeModelTypeSyncBridge::ApplySyncChanges(
     std::unique_ptr<MetadataChangeList> metadata_changes,
     EntityChangeList entity_changes) {