Align IndexedDB metadata rollback on transaction abort to spec.

third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 119 matching lines @@
     State m_state = Active;
     bool m_hasPendingActivity = true;
     bool m_contextStopped = false;
     Member<DOMException> m_error;
 
     HeapListHashSet<Member<IDBRequest>> m_requestList;
 
     typedef HeapHashMap<String, Member<IDBObjectStore>> IDBObjectStoreMap;
     IDBObjectStoreMap m_objectStoreMap;
 
-    // Used to mark stores created in an aborted upgrade transaction as
-    // deleted.
-    HeapHashSet<Member<IDBObjectStore>> m_createdObjectStores;
-
-    // Used to notify object stores (which are no longer in m_objectStoreMap)
-    // when the transaction is finished.
+    // Tracks the stores deleted in this transaction.
+    //
+    // All the other stores modified in this transaction must be in
+    // m_objectStoreMap.
     HeapHashSet<Member<IDBObjectStore>> m_deletedObjectStores;
 
-    // Holds stores created, deleted, or used during upgrade transactions to
-    // reset metadata in case of abort.
-    HeapHashMap<Member<IDBObjectStore>, IDBObjectStoreMetadata> m_objectStoreCleanupMap;
     IDBDatabaseMetadata m_previousMetadata;
 };
 
 } // namespace blink
 
 #endif // IDBTransaction_h