Send IndexedDB observations through IDBDatabaseCallbacks.

third_party/WebKit/public/platform/modules/indexeddb/WebIDBObserver.h

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// This class makes the blink::IDBObserver visible to the content layer by
-// holding a reference to it.
-
-#ifndef WebIDBObserver_h
-#define WebIDBObserver_h
-
-#include "public/platform/WebVector.h"
-#include "public/platform/modules/indexeddb/WebIDBTypes.h"
-#include <bitset>
-
-namespace blink {
-
-struct WebIDBObservation;
-
-class WebIDBObserver {
- public:
-  virtual ~WebIDBObserver() {}
-
-  virtual bool transaction() const = 0;
-  virtual bool noRecords() const = 0;
-  virtual bool values() const = 0;
-  virtual const std::bitset<WebIDBOperationTypeCount>& operationTypes()
-      const = 0;
-  virtual void onChange(const WebVector<WebIDBObservation>&,
-                        const WebVector<int32_t>& observationIndex) = 0;
-};
-
-}  // namespace blink
-
-#endif  // WebIDBObserver_h