Revert of Refactor BeforeInstallPromptEvent to use ScriptPromiseProperty

Source/modules/app_banner/AppBannerCallbacks.h

-// Copyright 2015 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.
-
-#ifndef AppBannerCallbacks_h
-#define AppBannerCallbacks_h
-
-#include "modules/app_banner/BeforeInstallPromptEvent.h"
-#include "public/platform/modules/app_banner/WebAppBannerClient.h"
-
-namespace blink {
-
-class AppBannerCallbacks : public WebAppBannerCallbacks {
-public:
-    explicit AppBannerCallbacks(UserChoiceProperty*);
-    ~AppBannerCallbacks() override = default;
-
-    // WebAppBannerCallbacks overrides.
-    void onSuccess(WebAppBannerPromptResult*) override;
-
-private:
-    Persistent<UserChoiceProperty> m_userChoice;
-};
-
-} // namespace blink
-
-#endif // AppBannerCallbacks_h