Align IndexedDB metadata rollback on transaction abort to spec.

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

Index: third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
diff --git a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
index 9e5fa8a27d4d1177dd9e4a241b6f719979a858ce..e3bd4b24d6464e6c9e95d63857aceb9f1b48132b 100644
--- a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
+++ b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.h
@@ -137,17 +137,12 @@ private:
     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;
 };