[Sync] Cleanup datatype configuration error handling.

components/sync_driver/failed_data_types_handler.h

Index: components/sync_driver/failed_data_types_handler.h
diff --git a/components/sync_driver/failed_data_types_handler.h b/components/sync_driver/failed_data_types_handler.h
index 93b6fae6ac6eb0532f4291fecc0516a6fe6c2fe0..4d13cdade45449f9ebeb3330d60150f31a74e691 100644
--- a/components/sync_driver/failed_data_types_handler.h
+++ b/components/sync_driver/failed_data_types_handler.h
@@ -61,13 +61,16 @@ class FailedDataTypesHandler {
   // Returns the types that cannot be configured due to not being ready.
   syncer::ModelTypeSet GetUnreadyErrorTypes() const;
 
+  // Returns the current unrecoverable error, if there is one.
+  syncer::SyncError GetUnrecoverableError() const;
+
  private:
   // Returns true if there are any types with errors.
   bool AnyFailedDataType() const;
 
-  // List of data types that failed due to unrecoverable errors and should
-  // be disabled.
-  TypeErrorMap unrecoverable_errors_;
+  // The current unrecoverable error, if one was encountered. There can only
+  // be one unrecoverable error at a time.
+  syncer::SyncError unrecoverable_error_;
 
   // List of data types that failed due to runtime errors and should be
   // disabled. These are different from unrecoverable_errors_ in that