IndexedDB: Have IDBCursor and IDBRequest explicitly break ref cycles

Source/modules/indexeddb/IDBCallbacks.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 23 matching lines @@
 #include "modules/indexeddb/IDBKey.h"
 #include "modules/indexeddb/IDBKeyPath.h"
 #include "public/platform/WebIDBCallbacks.h"
 #include "wtf/RefCounted.h"
 
 namespace WebCore {
 
 class DOMError;
 class IDBCursorBackendInterface;
 
-class IDBCallbacks : public RefCounted<IDBCallbacks> {
+class IDBCallbacks : public WTF::RefCountedBase {
 public:
     virtual ~IDBCallbacks() { }
+    virtual void deref() = 0;
+
 
     virtual void onError(PassRefPtr<DOMError>) = 0;
     // From IDBFactory.webkitGetDatabaseNames()
     virtual void onSuccess(const Vector<String>&) = 0;
     // From IDBObjectStore/IDBIndex.openCursor(), IDBIndex.openKeyCursor()
     virtual void onSuccess(PassRefPtr<IDBCursorBackendInterface>, PassRefPtr<IDBKey>, PassRefPtr<IDBKey> primaryKey, PassRefPtr<SharedBuffer>) = 0;
     // From IDBObjectStore.add()/put(), IDBIndex.getKey()
     virtual void onSuccess(PassRefPtr<IDBKey>) = 0;
     // From IDBObjectStore/IDBIndex.get()/count(), and various methods that yield null/undefined.
     virtual void onSuccess(PassRefPtr<SharedBuffer>) = 0;
@@ skipping 10 matching lines @@
     // From IDBFactory.open()/deleteDatabase()
     virtual void onBlocked(int64_t /* existingVersion */) { ASSERT_NOT_REACHED(); }
     // From IDBFactory.open()
     virtual void onUpgradeNeeded(int64_t /* oldVersion */, PassRefPtr<IDBDatabaseBackendInterface>, const IDBDatabaseMetadata&, WebKit::WebIDBCallbacks::DataLoss dataLoss) { ASSERT_NOT_REACHED(); }
     virtual void onSuccess(PassRefPtr<IDBDatabaseBackendInterface>, const IDBDatabaseMetadata&) { ASSERT_NOT_REACHED(); }
 };
 
 } // namespace WebCore
 
 #endif // IDBCallbacks_h