[Sync] Introduce ModelError for USS error handling.

components/autofill/core/browser/webdata/autocomplete_sync_bridge.h

Index: components/autofill/core/browser/webdata/autocomplete_sync_bridge.h
diff --git a/components/autofill/core/browser/webdata/autocomplete_sync_bridge.h b/components/autofill/core/browser/webdata/autocomplete_sync_bridge.h
index 8bf3460d79554dc957fcb8274265c455c4523eb1..ab9dd7a2013ca38e2baf7f1355eb5a66abbae61c 100644
--- a/components/autofill/core/browser/webdata/autocomplete_sync_bridge.h
+++ b/components/autofill/core/browser/webdata/autocomplete_sync_bridge.h
@@ -16,10 +16,6 @@
 #include "components/sync/model/metadata_change_list.h"
 #include "components/sync/model/model_type_sync_bridge.h"
 
-namespace syncer {
-class SyncError;
-}
-
 namespace autofill {
 
 class AutofillTable;
@@ -46,10 +42,10 @@ class AutocompleteSyncBridge : public base::SupportsUserData::Data,
   // syncer::ModelTypeService implementation.
   std::unique_ptr<syncer::MetadataChangeList> CreateMetadataChangeList()
       override;
-  syncer::SyncError MergeSyncData(
+  syncer::ModelError MergeSyncData(
       std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
       syncer::EntityDataMap entity_data_map) override;
-  syncer::SyncError ApplySyncChanges(
+  syncer::ModelError ApplySyncChanges(
       std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
       syncer::EntityChangeList entity_changes) override;
   void GetData(StorageKeyList storage_keys, DataCallback callback) override;