[Sync] Migrate bridge implementations to change list based MergeSyncData

components/sync/model/model_type_sync_bridge.cc

Index: components/sync/model/model_type_sync_bridge.cc
diff --git a/components/sync/model/model_type_sync_bridge.cc b/components/sync/model/model_type_sync_bridge.cc
index e4c6f87b6c1282ffd828a7c44f455530cbabe672..45347e84b66b69126d6370e81ddcfeb693e30a55 100644
--- a/components/sync/model/model_type_sync_bridge.cc
+++ b/components/sync/model/model_type_sync_bridge.cc
@@ -21,19 +21,6 @@ ModelTypeSyncBridge::ModelTypeSyncBridge(
 
 ModelTypeSyncBridge::~ModelTypeSyncBridge() {}
 
-base::Optional<ModelError> ModelTypeSyncBridge::MergeSyncData(
-    std::unique_ptr<MetadataChangeList> metadata_change_list,
-    EntityChangeList entity_data) {
-  EntityDataMap entity_data_map;
-  for (const auto& change : entity_data) {
-    DCHECK_EQ(EntityChange::ACTION_ADD, change.type());
-    DCHECK(!change.storage_key().empty());
-    DCHECK(entity_data_map.find(change.storage_key()) == entity_data_map.end());
-    entity_data_map.emplace(change.storage_key(), change.data_ptr());
-  }
-  return MergeSyncData(std::move(metadata_change_list), entity_data_map);
-}
-
 bool ModelTypeSyncBridge::SupportsGetStorageKey() const {
   return true;
 }