IndexedDB: Have IDBCursor and IDBRequest explicitly break ref cycles

Source/modules/indexeddb/IDBTransaction.h

Index: Source/modules/indexeddb/IDBTransaction.h
diff --git a/Source/modules/indexeddb/IDBTransaction.h b/Source/modules/indexeddb/IDBTransaction.h
index ef93634fef807645a03ac6f6731f18e088681bed..b11a50bcf90c93438c8da9337443ee807675f99a 100644
--- a/Source/modules/indexeddb/IDBTransaction.h
+++ b/Source/modules/indexeddb/IDBTransaction.h
@@ -79,16 +79,6 @@ public:
     PassRefPtr<IDBObjectStore> objectStore(const String& name, ExceptionState&);
     void abort(ExceptionState&);
 
-    class OpenCursorNotifier {
-    public:
-        OpenCursorNotifier(PassRefPtr<IDBTransaction>, IDBCursor*);
-        ~OpenCursorNotifier();
-        void cursorFinished();
-    private:
-        RefPtr<IDBTransaction> m_transaction;
-        IDBCursor* m_cursor;
-    };
-
     void registerRequest(IDBRequest*);
     void unregisterRequest(IDBRequest*);
     void objectStoreCreated(const String&, PassRefPtr<IDBObjectStore>);
@@ -122,10 +112,6 @@ private:
     IDBTransaction(ScriptExecutionContext*, int64_t, const Vector<String>&, IndexedDB::TransactionMode, IDBDatabase*, IDBOpenDBRequest*, const IDBDatabaseMetadata&);
 
     void enqueueEvent(PassRefPtr<Event>);
-    void closeOpenCursors();
-
-    void registerOpenCursor(IDBCursor*);
-    void unregisterOpenCursor(IDBCursor*);
 
     // EventTarget
     virtual void refEventTarget() { ref(); }
@@ -162,8 +148,6 @@ private:
     IDBObjectStoreMetadataMap m_objectStoreCleanupMap;
     IDBDatabaseMetadata m_previousMetadata;
 
-    HashSet<IDBCursor*> m_openCursors;
-
     EventTargetData m_eventTargetData;
 };